Sounds like Anitvirus 2009. My dh just got it off his computer using Malwarebytes. Av 2009 caused the computer to do some squirrly stuff too.
And scans with virus/spamware programs (for instance McAfee & AdAware) could not get rid of it.
We got our version of Malwarebyts as well as advice from BleepingComputer.com. But there are other places out there.
Malwarebytes downloaded but wouldn’t start up. Our problem was that this virus seems to recoginize the program and “prohibited” it from running.
As was suggested we had to rename it and then run it. It worked but it took 3 or more scans till it was all gone.
I ran it in safe mode and it worked. It took an hour to scan everything, but there was no other way. This virus/trojan is hideous. The perpetrator should get the death penalty.