Hey Sonya!
Please hold off on re-enabling Spysweeper until we're finished fixing your system--we wouldn't want it to interfere with any changes that still have to be made, which is why it was disabled in the first place.
How long has this restart problem been occuring? Has it just recently started?
Please go to the Run box on the Start Menu and type in or copy/paste
sfc /scannow. (there is a space between sfc and /)
This command will immediately initiate the Windows File Protection service to scan all protected files and verify their integrity, replacing any files with which it finds a problem. You may be prompted to insert the Windows XP install disc, so have it handy.
Let me know the results of that, and whether the problem is still occuring after that finishes.