. I had malware bytes and it wouldnt run
If you have Malware defense, it actually deletes mbam.exe,thats why it wont run,in the link posted by scott, there is a detailed description how to remove this virus.There is also a download link for a ' renamed' mbam.exe which you should place in C:\program files\Malwarebytes' Anti-Malware\ folder.
It is important to kill the process before removal, use Rkill ( in the link )
However the fact that it deleted mbam.exe suggests that, ( as someone else said ) There may be another element ( tdss )
So start by running the tdss killer posted by techlike99, then follow the link
http://www.bleepingcomputer.com/virus-removal/remove-malware-defenseto the letter