I actually want to do a clean sweep of the entire thing, meaning clean up my hard drive, kill whatever viruses are on it, etc. I dont really have anything important on it that I would need to back up, but I have no idea how I would go about wiping all the garbage from the HD besides manually deleting everything.

I also want to get rid of Vista. I know there are other OS out there, but I want something light and doesnt take up all my RAM and maybe on the free side.

Are there any programs out there that are a must have that would better organize my pc?

I know these are broad questions and I appreciate anyone who tries to help!