Try Kaspersky TDSSKiller You may have to download it to another PC and rename it, then run it on the infected box from a USB drive. If it’s blocked or gets deleted when you open the drive or try to run it, you’ll have to either connect the infected drive to a clean PC or boot the infected PC from another drive.
I keep a bare bones second install of Windows on another drive just for such cases. I had to use it to run TDSSKiller to remove a rootkit I got hit with in a drive-by.