Internet & Windows Explorer Crash

Have XP home w/ SP1. Just reformatted, but prior to reformatting I had two errors w/ Internet and Windows Explorer. Unable to right click and get message that they have to shut down. Appears to be shell32… After shut down, desktop refreshes until it happens again. Very sporadic. It will also do the same thing when Internet is up and I click on file, etc. I’ve run SpySweeper, always run Windows Washer, Norton AV and Tweaknow 2005. This was a problem before reformatting and after. Any suggestions?