I'm taking this one!
You probably have System restore enabled on that drive.
If you want to turn it off, go to the system properties, click on the System Restore tab, and un-check system restore. If you DO in fact like it, you can turn it down as far as it will go (we all know you don't need 12GB of System restore...
I personally never use it, because whenever I've had catastrophic PC problems, I always cant even get into Windows... and their rollback thing seems pretty useless to me...
I can't remember if that was the correct way to get to selective drive disableing... but you can turn it off on specific drives if you have multiple of them.
Another thing to do is make sure your recycle bin isnt too big.
You're the guy from that hamburger train, right?