This is a rogue antimalware program, and its variants have been reported more and more frequently over the past year or so, and especially over the last ~6months (based on my recollection of reports on forums.)
http://www.malwarebytes.org/mbam.php (MBAM) is one of the antimalware scanners that has had a lot of success with this nasty. I believe it is installed by a variant of the vundo or virtumonde family of trojan. New variants are released frequently, which is possibly one of the reasons Avast hasn't nailed the one on your PC.
Download and install MalwareBytesAntiMalware, update it, and run a quick scan. Quarantine anything found. It might ask to delete files on reboot, if so, OK/Yes out of the prompt, and reboot straight away.
If you have problems with the scan, try it again in safe mode.
If you have problems installing MBAM, try re-naming the installer file.
If you can install it but then cannot open the program, navigate to the program file folder containing it, and rename the main executable.
Or if you have any other problems, please post back.
Another program with a very good reputation is
http://www.superantispyware.com/download.html You might want to download and then run both (in turn).
In both cases, download the free version/s.