I'm trying to fix 5 year old Macbook for some one .The problem is hard-drive space used up but the person has very little pictures ,music and work on the computer. Some how only 7GB free of the 80GB hard-drive. There is a similar thread http://forums.macrumors.com/showthread.php?t=672477 Thread never got resolved. well normally when I'm trying fix the same problem on PC running windows it is do to. 1.Bad sector 2.swap file /page file 3.hidden OS system support files 4.malware 5.windows files to keep OS running and windows needs lots of files and I mean lots, lots and lots of files!!! But do not have that much experience here. What could the problem be.