A reinstall would have removed your saved files.
First, I'd try SFC (System File Checker). It can fix certain issues in Windows where specific system files get corrupted, deleted, or infected. Basically the System File Protection watches the system files and checks their integrity against it's knowledge of what these files are supposed to look like. Generally if a system file get's "messed with" windows will let you know and give you the option to dissallow the change, sometimes you don't get this option though. The System File Checker is a command line utility that will initiate a scan of all the system files to make sure they are in their original state, present on the system, and or working properly. It's an easy tool to use but the user HAS to have an XP disk for it to work.
Place your Windows XP CD in your CD ROM drive and follow the instructions below.
Start > Run > cmd then type
sfc /scannow (note the space)
let this run untill you get a message saying it is complete.
SFC - system file checker, retrieves the correct version of the file from %Systemroot%\System32\Dllcache or the Windows installation source files, and then replaces the incorrect file.
If you want to see what was replaced, right click My Computer > manage, expand event viewer > system.
If you did actually begin the install, then cancel out, and/or SFC doesn't help, you might try a repair install.
*** Be aware, repairing Windows does not cause you to lose any data or files, but you will have to reinstall other software you had installed, as well as device drivers and all the Windows hotfixes and updates that you've installed since you put the computer intos service.
To repair Windows, put the Windows CD in your CD drive. Power the computer down, then power it back on.
When the "Press any key to boot from CD" message is displayed on your screen, press a key to start your computer from the Windows XP CD. If you don't get this message the first time, reboot and press F12 for the boot menu when the Windows splash screen first appears.
When you see the following message displayed on the Welcome to Setup screen, press ENTER....
To setup Windows XP now, press ENTER.....
At this point an option to press R to enter the Recovery Console is displayed.
Do not select this option.....
On the Windows XP Licensing Agreement screen, press F8 to agree to the license agreement.
Make sure that your current installation of Windows XP is selected in the box, and then press the R key to repair Windows XP......
Follow the instructions on the screen to complete Setup.....
This will repair XP and put everything back to as it first was.....
Again, you will have to reinstall any Hotfixes and OS updates. You may have to reinstall other software you had installed.