Picked up a Virus

Hey all, I've picked up a virus. It seems to be up and down, at times my computer can't really do anything and at other times the computer is working normally so i'm not sure how severe it is. Just trying to decide what to do about it.
I'm using AVG antivirus. I need a way to get the virus and infected files off my computer. Is there a freeware program that could clean it all up? Should I consider taking my computer into a shop, I do have a good one that I use consistently (although i am not computer illiterate)? or should I perform a destructive recovery and reset everything to the off-the-shelf point.
I have two hard drives and most of my music and other media is on the second drive, I don't think there is any infection on it so I can unplug it when i do the recovery to save all the files I want saved.
Any and all help is appreciated, Thanks!
I'm using AVG antivirus. I need a way to get the virus and infected files off my computer. Is there a freeware program that could clean it all up? Should I consider taking my computer into a shop, I do have a good one that I use consistently (although i am not computer illiterate)? or should I perform a destructive recovery and reset everything to the off-the-shelf point.
I have two hard drives and most of my music and other media is on the second drive, I don't think there is any infection on it so I can unplug it when i do the recovery to save all the files I want saved.
Any and all help is appreciated, Thanks!