I upgraded from XP to Vista, and I seem to have about 2 gigs of space missing on my OS partition. I'm assuming theres hidden XP stuff left over, because my friend did a fresh install of vista and it took up way less room. My windows partition is 20 gigs, and I'm having space issues. Theres a hidden "ProgramData" folder; can I delete that? Some games insist on extracting to C: before installing, and this can be a pain sometimes when I only have around 3 gigs left. What is taking up so much room!?