I have a 55 gb hard drive on my IBM laptop. All files and folders added up amount to about 20 gb, but Windows XP was showing that I have used 51 GB. I deleted about 3 or 4 gb of useless files and available space went up to 4 gb or so, and then it slowly decreased again. So something was eating up free space.

I ran chkdsk at startup, nothing happened. Ran ad-aware and deleted a few "critical objects", and anti-virus detected and deleted a virus called "downloader.swif". I don't know if the problem is fixed yet, but the question how do I reclaim the disk space lost? SpaceMonger shows that there are a 24 GB "unscannable" sector

Have you done a disk clean up. Oftenly Temporary files and Internet files loves to eat up your memory space.

Check your recycle bin. There might be large files there you need to clean up. Oh, and CG - it's hard drive space, not memory space to be more precise. Memory is temporary - resets every time you reboot your computer.

There's several programs that you can download to see how much space you have. There's one (I forget the name, but I think it's on sourceforge -- it has a tree as an icon) that shows a graphical representation of what's in your folders as blocks.

could it be that your swap-file is set to be able to grow?

I usually set my swap file at a fixed size (about 1.5 * the RAM size)

That virus -- see what Symantec (http://www.symantec.com/security_response/writeup.jsp?docid=2006-052112-3621-99) says about it.

It's probably downloading things to your hard drive. You might have other virus in your system.

Since the virus is recent, files it downloaded would have been accessed recently too. So I don't think Disk Cleanup can find them.

I don't have a solution except to browse into all the folders and delete things you know for certain you don't need. I don't believe the downloader virus would be so nice as to leave a log behind.

Try Sequoia View (http://w3.win.tue.nl/nl/onderzoek/onderzoek_informatica/visualization/sequoiaview//) and see if it can find any abnormally large file blocks.

Delete everything in recycle bin and %temp%

I probably have the same virus :(, it keeps filling my documents\videos folder :mischief:.

But for real, you might also want to lower the amount of space which is reserved for windows restore point (it's under drive properties, percentage can be lowered there). Another way to free some space is check how big your IE cache setting is (if you use Internet explorer, that is) and lower it since by default it's far too big imho.

A sure sign of adwares, spywares and virus!

Say man, did you noticed your PC getting slower in processing data? In short, LOTS OF LAGS???