BHO.DLL was not found

Can someone please help me every time i restart my laptop i get a message saying(This application has failed to start because BHO.DLL was not found.reinstalling the application may fix this problem) now i have googled this problem and many say it is a virus and is easy to remove is it my ass easy i scanned it with avg and that done no good i also used regcure that someone suggested but still nothing.
can someone tell me is this damaging my laptop and what and how did i get it and more importently how the hell do i get rid of it. cheers