My sister was working on some Excel documents, minimized them and put the computer to sleep mode. About a week later, I ran OnyX to improve the speed and stuff, it had to close Excel and the minimized windows. So far so good. Now when my sister wanted to open those Excel documents again, two (of three) of them were gone. I know her filing system is terrible, but I get the impression that she did actually search her computer thoroughly, and found nothing. How can it be that these files are simply gone?