My hard drives originally has 920gb of storage. I decided to download and clean install window 7 via torrent (at the time I think I had about 300gb of free space left) I'm pretty sure when I did the clean install it worked., because most of my files were gone. I only had like windows, and window old files, and files like that. When I checked my had drives it went down to from 300gb to 280gb or so. I downloaded advanced system care and ran the disk doctor. It showed me all the files my pc had and how much gb were in them. By estimating there couldn't of been more than 35gb of data between all the files that were on my computer after the clean install. I'm basically trying to say that I cant delete that 500gb of data nor can I even find it. Its like its invisible or something. I deleted the windows old folder but that only deleted like 5 to 10 gb.