Where did my space go?

[mknabster]

I try to monitor all the free space I have on my computer the best I can, but lately, it seems to have slipped underneath my fingers, and now I can't figure out what's there, and when my free space went. Before, I have 86GBs left on my hard drive, now, with hardly any change to the drive in terms of addition of files, I have 50GBs left. I'm going through all my folders, trying to see if i forgot about something, but nothing is in my folders. I went through and found my folders including applications, has 32GBs used. But where did the other 79GB go to? I can't figure it out. I know i need to get another hard drive, but I wanted to try to hold out until the end of this semester, but this just doesn't make any sense.