Originally Posted by this_is_gav 
Not going to help at all. What you need to do is remove your FF profile, which resides in C:\Documents and Settings\%username%\Application Data\Mozilla\Firefox\Profiles\%random folder name% - 'Application Data' is a hidden folder, so make sure you're showing all files.
Move the contents elsewhere on your hard drive, and FF will start a-fresh next time it loads. Import your bookmarks.html file if you want to keep them.
Done that before reinstalling
Can anyone else access those sites ok under ff?