My computer has apparently been hit be a virus. When I do a search on
Google and click on a result an ad page comes up. Also, I'm having trouble
creating some queries in Microsoft Access. Also, when I boot the computer
I get 2 messages saying a file is missing.

So I tried to do a system restore. It keeps telling me that it can't do
the restore because the computer has not been changed. I've tried it using
several different dates going back weeks. How can I fix this? I'm using
Windows XP Professional.