I have Win 7 Pro 64bit installed on a SSD 250GB along with my Programs and Data on a second SATA Hard Drive. Recently when I looked at my C: SSD from My Computer, I noticed the Used Space Bar was Red and I only had a small value of Free Space left (13GB). I used CCleaner to clean up Temporary Files Etc, Emptied the Recycle Bin. This action did not have much affect on increasing Free Space. I left the issue for a few days as I had a lot of other work to do. Yesterday, I thought I would have another look at this issue, as I was thinking I might have to upgrade to a 500GB SSD. Low and Behold, when I checked the Drives in MY Computer, my C: SSD was now Blue and showing 108GB Free Space. I am struggling to understand how this could have happened as I had done nothing to contribute to this change to Free Space. Has WIN 7 Pro got some built in Archiving Feature I am not aware of that could have compressed the Files on C: SSD. Can someone please throw some light on this issue.