There are two possibilities. There is either a program in the background that is using the file, or the install program itself is using the file. This only affects installation. It does not affect the way the program runs once installed properly. There are two possible solutions:

I. End Task on all processes and programs running on your windows system.

    A. Exit all programs currently running.

    B. Hit Ctrl+Alt+Del once to get a task list of all other programs

    C. End task on all processes except explorer and systray.

    D. Try the installation again. 

II. Reboot the computer in "Safe Mode" (to do this please see the Windows help file).

    A. Start Windows in safe mode. Below are the instructions for running Windows 2000 in safe mode. If you have another operating system, please check your windows help for step-by-step instructions on how to do this.

    1. Click Options, and then click Print to print these instructions. They will not be available after you shut your computer down in step 2.
    2. Click Start, and then click Shut Down.
    3. Click Restart, and then click OK.
    4. When you see the message Please select the operating system to start, press F8.
    5. Use the arrow keys to highlight the appropriate safe mode option, and then press ENTER. NUM LOCK must be off before the arrow keys on the numeric keypad will function.
    6. Use the arrow keys to highlight an operating system, and then press ENTER. 

    B. Do the installation again. 

    C. Reboot the computer in regular Windows (not safe mode).