I have a new HP computer with 750 Gb HDD. When I right click C: drive, it says that I am using 90.3 Gb of disk space; however, when I add up all the programs, user accounts, documents, windows, etc... I come up with about 32 Gb in used space. I just upgraded from Vista Home premium 64 bit to Vista Ultimate 64 bit yesterday and saw a 10 Gb increase in disk usage. I removed all the add ons and program stubs from %temp%. I understand bloatware but this is ridiculous. Any solutions to this? Did windows just grab empty disk space and claim it as it's own, showing up as used one way and empty another?