Angels have the Phone Box
First of all, MBAM (Malwarebytes Antimalware) Free should do the job just fine getting rid of them, but you have to go into the settings and tick the box to scan for Rootkits. Then do the custom scan, selecting the entire C drive. The paid version should prevent them from getting on your system in the first place.
You may also want to run ADWCleaner, just to clean up things.
Please also have a look at your installed applications and make sure nothing shady is in there.