Ok, so after yet another virus scare from my brothers side of the computer, I decided to tell him he HAD to invest in an external HDD so we could back stuff up in case I end up for whatever reason having to reformat, or we just suffer some inexplicable data loss.
I'm not sure exactly where to start though. I've done some googling, but not really sure still. One thing that sounded appealing, albeit initially time consuming, was the idea of making a ghost image of my main HDD, which could be immediately restored to the HDD in case of any problems.
With this in mind, we have a 1TB external HDD, and a ~200GB windows partition. Do I have to back up the ENTIRE HDD or can I simply create a ghost image of the windows C:\ partition, to be restored if need be? Also, how can I set this up, so that space that's not needed for the backup, is freely usable for other purposes? (I'm thinking music/art storage to be honest)
Any and all help appreciated, any extra info needed, just ask.

www.aeriagames.com <-They have some decent ones