|Most Virus and Spyware scans are likely to work better in Windows Safe-Mode.|
There may be a fix here --
This page has alot of XP fixes
Some require the download of a VBS, or Regedits file.
So, read at the top of that page--
"To use the Regedits" or "To use the VBS files"
Then go to line 214, then click item in right hand column.