Run a scan with Malwarebytes' Anti Malware. MBAM will scan memory and registry to remove most threats. Good for ones like this, because it has to be on the memory to be launching ads.
Then, run a Lavasoft Ad-Aware scan. Both of these programs are free and won't take time to download/scan.
Post your results.
EDIT:
Disconnect yourself from the internet.
Use another computer to download the installer of AVG.
Copy it to yours and install it, then run a system scan.
Good point with the internet thing, it escaped my mind. I'd try the others before AVG first though.
