Need HELP with Virus on my computer!! (A.S.A.P)?

[GoTz DaT J.C LuV]

I need help with a virus thats just got on my computer.. anybody know how to get it off for free.I know there's programs out there that are free but i don't know which ones really work so please help me out i would appreciate it =) A.S.A.P

Oh and which ones do you personally use?.... and which do you recommend ?
THANKS ;)
the virus is called trojan i think