Ok Mac boys, tune out.

I would appreciate some advice from the PC guys here on this subject. I think I have picked up a nasty I can't identify. In the middle of posting my comment on the FX1200 thread, my Firefox tab was hijacked to an advert for bit-defender, a product I had been reviewing to fix an issue I fear I have. I think the system is slow responding too, not badly, but enough to make me suspicious.

I use Webroot secure Anywhere as my main protection, but, periodically, and after suspected attacks, run Malware bytes which yesterday ripped out a couple of dozen minor threats, and then on its 2nd scan reported "clean". There are so many solutions out there reporting false positives, and failing to find real threats, and I don't want to be running every product on the market, but I am interested in recommendations for a real killer

The background is I bought a new Nikon camera, and the 64 bit software wouldn't start. I eventually solved it by replacing 4 dll files, but prior to that, to my regret, googled for a "magic fix" and installed ReImage repair. This is still installed, and I am waiting to uninstall it in the manner required for a refund, but I doubt it is directly the cause of the problem. But I think I might have got suckered into a couple of others whilst trying to download Microsofts own malware removal tool.

Any thoughts?