Go to Start > Control Panel > Add or Remove Programs make sure the Show Updates option (at the top) is checked. Then scroll down to Windows XP - Software Updates listing & search for the most recently dated update(s). Make note of the "KBXXXXXX" number & check it out on the MS site. When you decide which update may be the offending one, highlight it & click Remove. Reboot & check if the problem is resolved.
If multiple updates were installed on the same date, you may have to repeat the above until you find the offending one. Make note of the KB number when you do, so that you can block it from being re-installed.
[Cheers]