before trying to reinstal windows try CTRL + ALT + Delete (Task Manager) for XP, run new... and go to (C

Windows then look for an icon resembeling a computer screen saying explorer.exe double click and open.
That should load ytour desktop if not then i think you better reinstall windows again
there is a way you can reinstall windows witout loosing any data, but you have to copy the data from the EX account, after reinstall go to C:\Documents & settings and look for the old accout you used to run on. all your data will still be there, if it isnt you probably have formatted your hard drive

which is annyoing hope i helped!
Thanks Jack!