Please. Please help

[len]

I have got
Smithgaurd-C. (PS Guard )
Smithguard-C MSVPS ( trojan ) and
ZLOB. Downloader.VCD (trojan )
on my PC and have tried everything to remove them with no efect. Is there anyone out there to help me please, It is doing my brain in

 

[Ian]

Which anti-virus do you have on your system at the moment?

There's a good guide for another user that had the same problem at another site with the same 3 nasties:
http://www.bleepingcomputer.com/forums/topic121490.html