Getting hammered with pop up adds here

Well, Firefox is a good start. At the top click on tools>add ons> and look for "adblock plus popup addon 0.3" add that to Firefox.

Go to tools>options>content tab and make sure you have "block pop up windows" checked.

I would also switch to Bing for your search engine, Yahoo, Google and the like can create some of the problems you are experiencing.

One more thing go to: http://www.malwarebytes.org/lp/lp4/?utm_source=bing&utm_medium=cpc&utm_campaign=search-brand-us

Download the free version, that is quite sufficient to do what you need. After you download it, run a scan on your PC, I bet it finds all kinds of Trojan Horses.

All you need to scan is your C drive, if you have an external drive it probably isn't necessary to scan it, as most things are written for C.