|When you said MalwareBytes "didn't help", do you mean it didn't find anything?|
Firstly look in "Control Panel > Programs and features" to make sure there are no unwanted programs that arrived without you knowing.
Also, in Firefox and Chrome see if there are any weird addons - they can be temporarily disabled if you are unsure what they all are.
Also run ADWCleaner too as there could be some hidden toolbars lurking:
Get it by using the blue "Download Now @ Bleepingcomputer" button.
It doesn't install in the normal sense but instead you just download and "Save" the file.
Run it by double clicking the downloaded file, first the Scan, then the Clean. Between the two is the opportunity to see the log to find out what it found.
Always pop back and let us know the outcome - thanks
message edited by Derek