How to remove Trojan-spy.bzub?

I have been trying to remove this virus, using Ad-aware and Spyware doctor, I have also installed AVG antivirus. But Spyware doctor only detect the virus but cannot remove it, while Ad-aware hasn't detected it.

Can someone please tell how to completely remove the virus,

it's slowing down my computer? Spyware doctor indicate the location of the file and the registry key, should I just delete this?

Another thing, what's the best firewall to use that is free which won't take up a lot of resources?

Thanks, I would greatly appreciate your help.

How to remove Trojan-spy.bzub?microsoft

Update and use your own antivirus or download one of the antivirus tools below and along with the spyware doctor and update them and restart your computer in safe mode ( tap F-8) during startup, then scan with the antivirus and the spyware doctor while in safe mode, this should find it so you can remove it; Please note that you should only run antivirus on your computer at one time,

Avira Antivirus free (Recommended)

http://www.free-av.com/antivirus/allinon...

PC Tools free antivirus, free, Note; only run one antivirus at a time;

http://www.pctools.com/free-antivirus/

Kaspersky free antivirus; Note, you should only run one antivirus at a time;

http://usa.kaspersky.com/products_servic...

This is a free antivirus tool called avg free, Note; You should only run one antivirus at a time;