How to check disk space usage?

I just noticed that my OS drive is 90% full and given that the drive size is 80gb and I use a separate drive for data I am a bit surprised. I am sure that the last time I checked at best it was half full.
I don't remember having downloaded any monsterfile/program apart from the recent windows updates incl. net framework but still don't see how this could have filled the drive.
Is there any program that allows me to see where the space has gone, ie which files are taking up the space?

 

You're essentially looking for these type items - http://www.snapfiles.com/Freeware/system/fwdisktools.html. TinyApps list a few simpler ones.
To mention, you'll find dmoz and _oogle offer a lot more if you thoughtfully mind your keywords - disk management usage analysis.

 

Thanks for that - just what I was looking for.

 

TreeSize Professional will do what you want too. It visually tracks down disk usage and lists what files occupies the most space.

 

My favorite of all time is an obscure one called Overdisk.

Sul.

 

OD's the one I couldn't remember. Approved by Willie P, TWICE!

 

I always liked this free one

Stats Viewer

http://www.contactplus.com/products/freestuff/stats.htm

and there's always Disktective -> http://www.disktective.com


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GetFileTypeDistribution will tell you how much of each file type is being used on a drive.

You find that you have, e.g., ooodles of PDF files, and other common file types.

 

WinDirStat portable
http://portableapps.com/apps/utilities/windirstat_portable

Treesize Free portable
http://www.portablefreeware.com/index.php?q=treesize free&m=Search

Both are also good.

 

Showman does the job for me.

http://www.satsignal.eu/software/disk.html#ShowMan

Al

 

I use a little program by Steffen Gerlach called Scanner. It's portable (no install) but includes .reg files for adding or deleting the program from the context menu. Tidy piece of work.

http://www.steffengerlach.de/freeware/