Computer Payment Enforcer Instruction Manual

Computer Payment Enforcer allows you to enforce payment for computers you have sold on credit, or are renting out, by locking access to the computer periodically unless an unlock code is entered. You can set the number of unlock codes required (the number of payments due on the computer). Once all payments have been made Computer Payment Enforcer, uninstalls itself to provide a clean computer.

Installing Computer Payment Enforcer on the customer computer

Run the cpearc.exe program on the target computer. You can put this program on a disk (floppy, thumb drive, etc.) and run it from there.

Computer Payment Enforcer will run as soon as it is installed. It will immediately ask you to create an administrative password. This password is very important, and will give you complete access to Computer Payment Enforcer. Note: The administrative password is case sensitive. This means that "Password" and "password" and "PASSWORD" are all different words. Be sure to remember the exact password you choose.

Once you have created the administrative password, you will see the main Computer Payment Enforcer control screen. You are now ready to configure Computer Payment Enforcer for that computer. The first thing to do is set up the payment schedule. To do this, click on the "Configure" menu and then on the "payments" option. This will take you to the Payment Configuration Form.

This form allows you to set the payment schedule. The first thing you need to do is set the number of payments. For example, it you require a payment in 30 days and another one in 60 days to pay off the computer, select 2. You can either type 2 in the "Number of payments to enforce" box or select 2 from the dropdown list.

Once you have input the number of payments, this number of payments will appear in the "Payment #" dropdown box. For example, if you input 3 payments for the number of payments, the options listed in the "Payment #" dropdown box will be 1, 2, and 3. You must now input the amount of time until each payment is due. Select the payment number from the "Payment #" dropdown box, then input the amount of time before that payment is due in the "Time to payment" box. For example, if you select 1 from the "Payment #" dropdown box and the first payment is due in 30 days, input 30 in the "Time to payment" box. If you select 2 in the "Payment #" dropdown box and the second payment is due in 60 days, input 60 in the "Time to payment" box. You must input the time to payment due for each of the payments. Note: If one payment is made up front, you would not include this payment in the list. You obviously should only include payments that are due after the customer takes possession of the computer.

You must also provide the start date for the countdown. For example, if the first payment is due 30 days after September 3, 2005, then put September 3, 2005 in the "Start Date" box. (You will have already input 30 days as the due date for the first payment.) All payment periods will be relative to this start date. The default when you first open the Payment Configuration Form.

You can also provide information about your company. This information will be displayed to the customer when Computer Payment Enforcer asks them to input their unlock code. This can be useful to providing the customer with information on where to pay their bill. You can input this information in the appropriate text boxes displayed on this screen. You do not have to provide any information you do not want to.

You can also alter the message that Computer Payment Enforcer displays to tell people about their time limit. The default "Until Due Announcement is "You have ##### days to your next payment on this computer.", where ##### is replaced by a number of days. This is the announcement that Computer Payment Enforcer displays on the screen when the computer boots up if the user still has time before a payment is due. Normally, this is an appropriate announcement. However, some people use Computer Payment Enforcer for other things than enforcing payments. For example, some companies use it to force people to come in for regular maintenance checkups, instead of making payments. In such a case, you can change "payment" in the announcement to "maintenance checkup" or something like that. Also, some people might want the message displayed in a language other than English. This feature allows you to display the message in another language by changing the announcement. In any case, it is absolutely necessary that the announcement contain the five pound signs (#) in a row. Computer Payment Enforcer will automatically replace these five pound signs with the number of days remaining when it displays the message.

You can also alter the wording of the announcement when time has expired and payment (or whatever) is due. Normally, this "Overdue Announcement is "Your payment on this computer is overdue.", but you can change it to something like "Your maintenance checkup is due" or change the language the prompt is written in.

There is one other significant change you can make. Normally, the Computer Payment Enforcer screen telling you how much time you have until your next payment will appear every time the computer boots up. In some cases, however, you might not want this screen to appear until a payment or other event is much closer. For example, if the payment is only due once a year, it might be a bit tedious for the screen to appear 365 times before the payment is due. Therefore, there is an option to limit the appearance of the screen to within a time span as the due date is approaching. For example, if the payment is due once a year, you might want the screen to start appearing 30 days before a payment is due. If the purpose of the screen is to force people to bring in the computer for maintenance every 60 days, you might want the screen to start appearing 3 or 4 days before maintenance is required. Therefore, the configuration screen has a box labeled " Days before due to display screen" where you can input a number or the word "All". The default is "All". However, if you want to limit the appearance of the screen to a number of days before the due date, you can input that number of days in this box. For example, to have the screen appear only within 30 days of the due date, input 30 in this box. Note that there is a potential danger to doing this. Once the program is running, the only way to display the Computer Payment Enforcer main screen (where you can change the program configuration) is to input the administrative password in the password box when the computer first boots up. If you set Computer Payment Enforcer to only display the screen as a payment due day is close, you lose the ability to display the main screen until a date arrives when the due date is within the selected time span and the screen starts appearing again. Therefore, use this only once you are experienced with Computer Payment Enforcer and are sure that you are not going to need access to the main screen. I strongly recommend that you leave this box with the default setting of "All" unless you REALLY do not want the screen to appear until shortly before the payment is due. (Note: If you do use this function of not displaying the warning label at every startup, there is a way to make payments early. You can go to the Add/Remove Programs (sometimes called Programs and Features on some operating systems) function in the Windows Control Panel. From there, you can input a payment code.)

Once you have input all the appropriate information, click on the "accept" button to save this information on this computer.

If there are a lot of pieces of information, it is convenient to be able to enter it all once and then transport it to other computers. You can save the information to a portable file named "CPEConf.dat" in your C drive root folder by clicking on the "Save Information" button. Note that this is different from the "Accept" button, which saves the information in an encrypted file hidden on this computer. To use the "CPEConf.dat" file, simply copy it to a floppy, thumb drive, or other portable media (best to delete it from this computer once you do that) and copy it into the C drive root folder of another computer. Then, when you install Computer Payment Enforcer on the other computer, you can click on the "Load Information" button on that Payment Configuration Form and load in all the data, such as company information and payment schedule. The only things not copied are the start date (allowing you to use the file any time) and the administrative password.

You may also want to be able to give the same sequence of identification and unlock codes to all your computers. Normally, Computer Payment Enforcer generates random identification and unlock codes for each computer it is installed on. You would then keep a record of these for each computer. You may find it more convenient to have the same codes for all your computers, even though this involves some risk of the codes getting out or being shared. If you do want to use the same codes for more than one computer, follow the following procedure. Before you click on the "Accept" button, click on the button labeled "Select Codes". Computer Payment Enforcer will ask you to input the number for the sequence of codes you want to use. Input a number and click on the "OK" button. (A five or six digit number is good.) Then click on the "Accept" button. Be sure to remember which number you input. Every computer you do this for and input the same number for will have the same sequence of identification and unlock codes. If you do not click on the labeled "Select Codes" button before you click on the "Accept" button, Computer Payment Enforcer will generate a random set of codes for each computer.

When you are finished inputting all the data you want and have clicked on the "Accept" button, you can close out the Payment Configuration Form by clicking on the "Close" button.

Registering Computer Payment Enforcer

Until you register this program and input the registration number on the registration screen, it will be possible to bypass the blocking screen by typing "CODE" in the text box. This information will be displayed on this screen. To register Computer Payment Enforcer, click on the Register menu on the main screen. Contact Leithauser Research by phone (1-386-410-6769), email (, or the Web site ( Make your payment, obtain your registration number, and put it in the registration screen text box, then click on the OK button. Once you do this, the message on the blocking screen instruction users to input "CODE" to bypass the screen will disappear and "CODE" will no longer bypass the blocking screen.

Viewing the ID codes and passwords

Once you have set up the payment schedule, you can click on the "View Codes" option under the "Configure" menu. This will display the View Codes Form. This form displays a list of all the ID codes generated for this computer and the corresponding password. Each pair is for one payment. If it is a short list, you can just copy it down on paper. You can also click on the Print button to send this list to your printer. You can also click on the Save to File button to save this list to a text file. If you decide to save to a file, Computer Payment Enforcer will display a screen that allows you to select the drive and folder to save the file to, and input the file name you want to use. A list of files already in the chosen file is displayed to make sure you do not use an existing file name. Select the drive and folder to put the file into (you should use a removable drive like a floppy disk or thumb drive so the person who gets the computer does not have this file), input a file name, and click on the Save button. Then remove the detachable drive from the computer. IF you decide not to save a file, you can just click on the Close button.

Once you have either copied the list of passwords, printed it, or saved it to a disk, you should keep it on file. When the customer makes a payment, you pull out your record of the ID numbers and corresponding passwords for that computer, select the correct password for the current payment, and send it to the customer. If you are confused about which password is the correct one for the current payment, you can have the customer send you his current ID code. This is displayed on the entry window described below.

Deleting this instruction manual

Before you ship the computer, you might want to delete this instruction manual to making it hard for the customer to figure out how the Computer Payment Enforcer program works. You can do that by clicking on the "Help" menu and them on the "Delete Instruction File" option. Once you do that, this manual is gone.

Computer Payment Enforcer in action

Once you have set up Computer Payment Enforcer as described above, every time you boot up the computer, Computer Payment Enforcer will display a window that informs the user how long until their next payment is due. There is a text box where they can input the next unlock code and a button to click on. It will also display the current ID code.

If there is still time before the next payment is due, the window will be less than full screen, and clicking on the button will remove it. You can input the unlock code as soon as you get it, but you can gain access to Windows without it if the payment is not due yet.

If a payment is due or overdue, the window will be full screen. There will be no way around it to use any programs. This screen will only disappear when you input the correct unlock code.

Once you input the unlock code, the window will disappear. If there are other payments due, the next time you reboot the computer, the window will show the time until the next payment is due. For example, suppose you had a payment due at 30 days and one due at 60 days. If you input the unlock code for the first payment 10 days before it is due, the next time you reboot the computer, the Window will show that you have 40 days until your next payment. If you input the unlock code for your last payment, the window will close and Computer Payment Enforcer will uninstall itself.

You can, however, bypass this window at any time by inputting the administrator password you set. This not only clears the window, it displays the Computer Payment Enforcer control panel. This is the only way to display this panel. It you ever need to get back to this panel, reboot the computer and input your administrator password in the entry window.

Computer Payment Enforcer has protection against the user moving the computer date back in order to circumvent Computer Payment Enforcer and gain free time. Basically, it will not allow you to set back the date while Computer Payment Enforcer is operating. The only exception is that it will allow you to set back the date while the Computer Payment Enforcer control panel is visible. Since the administrative password is necessary to view this panel, this should not allow unauthorized changes in the date. However, if you need to change the computer's date, simply input the administrative password when the computer boots up to show the control panel and you will be able to set the date.

Uninstalling Computer Payment Enforcer

As explained previously, Computer Payment Enforcer will automatically uninstall itself when the customer inputs the last unlock code after their last payment. However, you can uninstall it sooner. Call up the control screen by inputting your administrator password on the initial screen. Click on the "Files" menu and then on the "Uninstall" option. Computer Payment Enforcer will ask you if you are sure, then ask for your administrator password, then ask you if you are sure again. It will then uninstall Computer Payment Enforcer. You can also uninstall Computer Payment Enforcer by going to the Windows Control Panel program and selecting either the Add/Remove Programs or the Programs and Features (depending on your operating system) function. You will be required to input your password to uninstall Computer Payment Enforcer early. If the last payment has been made, however, it will not be necessary to input this password.

Bug reports and suggestions

Reports of problems or suggestions for improvement are welcome. Send such reports or suggestions to:

David Leithauser
Leithauser Research
821 SnapDragon Drive
New Smyrna Beach, FL 32168

You also can send email to In cases of emergency, you can call Leithauser Research at (386) 410-6769 between the hours of 10 AM and 6 PM ET.

If I feel that the improvement would be of interest to most users, I will make it for free and send you the improved version. If the improvement is unusual and suited only to your specific needs, I can give you a price quote for a customized version (see below).

Custom programming

Leithauser Research does custom programming. If you would like a custom program of any type written, please contact me at the above address for Leithauser Research. Describe the program you would like written in as much detail as possible and I will give you a price estimate.

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