Aqua-Soft ForumsI have noticed that for some reason i have disk space that has just seemingly disappeared. I don't know where it went, or what it is, because i added up everything thats visible on the drive and it doesnt equal up to the amount of space on it. Can someone help me?
Hard Disk Houdini
What about things that are invisible? "Show hidden items" is your best friend 
Sometimes caches and preferences that are stored on there can take up a lot of space.
Also, could you tell me the differences? What is the actual space on the drive, how much does it say you've consumed, and how much did your calculations tell you is on there?
Windows loves doing this.
I've got Vista, and sometimes I've got 29GB free, other times I have 21. It's got to cache, memory usage, and program prefs.
pagefile, aka swap. Clear that up.
It's a 20GB (which evens out to about 18.6GB) that windowsbox is installed on. It say's i currently have about 1.41GB. Today it was at around 297MB :confused: until i deleted all the system restore points and did about 4 disc cleanups. When i multi-select everything on the drive, it comes out to about 10GB.
And yes, i've viewed the invisible files as well, i still dont see anything that would explain it.
Check all of your preferences, caches, old apps that you deleted but didn't remove bits and pieces of, just anything.
you can also try by defragging the disk and free the disk space on the start menu 
that always helps
no offence but the advice above doesnt help your question. if you dont know where all your storage went, use windirstat,
Also, if you're ever on a Mac, Disk Inventory X does the same.
turn off hibernating, hiberfil.sys takes up as much space on your hd as you have ram.