Anti-Virus program

Ok, my main hard drive is an 8GB drive. My slave is 250GB but the main is filling up. But I have cleared it out. I check which folders holds the most space, go into the folder, highlight all the folders (including the invisible ones) and then it says like 4MB total, when it said 578MB before I went into the folder. So I think I have a virus because my computer runs kinda shitty. Does anyone have an install for a GOOD virus removal program, or know where I can download one. PLEASE HELP!!!!!!!


EDIT: Ok, Somehow my sound drivers and some other stuff got deleted, so I'm formatting now. I'll check responses after it's finished.

Ok, I ran a virus program and it found a folder called C:\Uploads , You can't even see the folder when you go into the C drive, not even as hidden. I try to delete the files in the folder, there are a ton, and it won't let me delete them. Does anyone know what to do????????!!!!!!!!!!!!!!!!!!!1111