How do i get rid of this spyware for good?

ok, i have PCsafe Adware/Spyware filter, and it keeps coming up with a trojan Horse called TopAV, it says restart to remove, i do, but it doesn’t go away, it is in a file called svchost.exe, which i think is a vital system file, so how do i remove it?

Scan again and try and remove in safe mode.
Spyware Doctor. http://www.pctools.com/
http://www.avast.com/ free

Keep Your PC Safe from Viruses, Spyware, Adware and others