hi and welcome to the fourms
what you could do is use revo unstaller this will remove everything to do with firefox will be gone you can download at
http://www.revouninstaller.com/
select advanced and remove everything you see and alos emtpy your recycle as some of the leftover files may go there and hopefully you can install 3.5
hope this works [img]/forums/images/graemlins/smile.gif[/img]