Hard drive space keeps disappearing..

[rynando]

The swap file shouldn't change size.

Yes this is true. If he's almost out of disk space the swap will expand to fill the space left by any recently deleted files until it gets back to it's allocated size. I just re-read the OP and he doesn't mention that he's out of space so never mind. I thought that's what was going on.

[sindominator]

Agree with "Jday"

Run Disk Cleanup followed by a Defragmentation and do it every 3 months or so.

Question: Do you have multiple profiles/login accounts on your computer. Wife, kids, roomate?