There's an IE download list at:
http://www.microsoft.com/windows/ie/...ads/Top10.mspx
Slightly ambiguous because when you select 'Internet Explorer 6 Service Pack 1', there's a line on the download page which reads: "Internet Explorer 6 SP1, the latest version of Internet Explorer for users not running Windows XP" yet two other lines suggest that this version IS for XP.
If you upgraded to IE6 you could uninstall the current copy by going: START-SETTINGS-CONTROL PANEL-ADD OR REMOVE PROGRAMS and select it for uninstallation and then re-install.
If your PC came with IE6 it should be on the Recovery Disc which came with the PC and you may be able to use that for uninstall/reinstall. (Be careful you don't reinstall the Operating System)
You could try running a virus scan and also download and run Spybot-Search & destroy.
Perhaps someone more knowledgeable than I will come up with another fix.