|I'm not going to suggest you use Firefox but sometimes temporarily installing it can prove whether your issue is with IE or something more general.|
For starters I would do two things:
First install then run ADWCleaner from here:
This will remove any hidden toolbars or their remnants. "Search" will tell you what it has found, "Delete" will remove all offenders.
Secondly install and run MalwareBytes freebie from here:
This will find and fix malware that AV's sometimes miss. It will also give you an idea whether there is anything of consequence lurking.
Always pop back and let us know the outcome - thanks