You are probably the victim of a virus attack. I suggest you try to back up any important files and/or folders you might want to keep. Then start a System Recovery and bring your PC back to it's original state..........Good Luck!!!!!!!!

Thought I would post an answer after having the same problem. Mine started with IE7 and getting error scripts on the page and a little yellow triangle showing up in the bottom left corner of IE. Upon clicking on triangle got a box with error in scripts on page, etc. Anyway it drove me crazy because it wouldnt run javascripts and vb scripts in the browser so only got limited stuff.
So I went into system restore to roll back but lo and behold blank screen!!! Managed to get in through another user profile but then system restore would run and not complete the restore. Tried numerous restore points but no go. Still had a white window with just the title bar showing system restore. Tried all sorts with registry, malware programmes, anti-virus programmes, etc. No luck.
In the end, I went to pc world and followed instructions on slipstreaming Xp (http://www.pcworld.com/... Essentially what I did was use my old win xp pro cd, downloaded service pack 3 from microsoft and used a programme called Autostreamer (http://www.pcworld.com/... merge my old win xp pro cd with service pack 3 so that I had an uptodate win xp cd.
Burnt to blank disk and put into dvd drive. From there I installed win xp as per prompts, but after it had collected data went for the upgrade without changing programs or saved files. Took about an hour. At end of it I had a clean registry again and those files that had become corrupted were reinstalled.
Result IE reinstalled fresh with IE 6, no problems with scripting!!!!! And system restore working good again. couldn't roll back anymore but didnt need to as everything okay again.
All instructions in the article in the link and links to required software downloads.