|Disable any resident (always running in the background) modules of anti-virus and anti-spyware programs when installing software. If you can't figure out how to do that, un-install them.|
Make sure the time and especialy the date is correct on the computer.
The messages may be about essential Windows system files orginally installed by Windows Setup.
It will ONLY work if you use an XP CD with SP2 updates included.
You need the CD to be in a drive.
Start - Run - type: cmd, click on OK
(If you get any error messages, they will show up in the black window.)
Type: sfc /scannow , press Enter.
Sometimes you need to click on try again or similar many times at the beginning, and occaisionally later on.
You may get no messages about what it did.
Reboot after it is finished.
Try the things that were not working before.