Hi. for the last 3 weeks something has been filling up my C: and I don't know what it is. when I reboot the lost space is back to free space. I have to reboot every 12 hours or so. I have a Sysinternals ProcMon Log for anyone to look at and tell me what the culprit is. WinDirStat doesn't help me just shows unknown as the largest space taken and growing on idle. Please Help???