I have been running this computer since 2003 and have never had a virus.... until this week.  I cannot figure out where it came from AND I cannot seem to get rid of it completely.  I have run complete scans with MalwareBytes and Avast.  Both of them find the little bugger, and seem to eliminate it.  Then the next day I start getting new windows opening for no reason.  Also seem to get redirected to miscellaneous websites when I do a Yahoo search.....

I am running Windows XP pro with the firewall up on a DSL connection.  I am using IE 8 for browsing.  I am running Avast antivirus.  I use Mailwasher to filter my email.

I know you guys will say to dump IE, but I've tried Firefox.... it is slow!

Any advise on what to run to clean up this computer?