Software That Removes Virus-Protection Programs

AvKiller

Av Killer is a software used to bypass Firewall,Antivirus & various security related software services on victim computer.Once the program is executed,AV Killer software will run in background & start killing all security related tasks on victims computer.These tasks include firewall,antivirus,windows defender & many other services.

Try a online antivirus scanner and a online anti-adware/malware/spyware scanner in safe(To get in safe mode Press "F8" upon boot up.
Select "Safe mode") mode with network to clean up your computer.

Antivirus: BitDefender Online scanner - will scan and remove threats.
Anti adware/spyware: SuperAntiSpyware  Online Scanner - will scan and remove threats.

Source 
Google