With even 1TB hard drives now commonplace, you might have thought the days of worrying about free drive space have gone forever. But you'd be wrong. Spend a few months installing new software, updating Windows, taking digital photos and downloading from the web, and it's amazing just how much of that drive real estate will disappear. So where has it all gone?

Folder Size makes it easy to track down the source of the problem, by adding the option of a new "Folder size" column to the Windows 2000 or XP Explorer (it doesn't work in Vista or Windows 7) that displays the total size of all the files it contains.

Click the new column header to sort by folder size, so the largest folders float to the top of the list, and that will show you where to look first. Then browse those folders looking for unnecessary files that you can safely delete. (Be careful, though - don't delete anything unless you're 100% sure that it's surplus to requirements.)

Deleting a large number of files will speed up operations like searches and (possibly) virus scans immediately. And that's good news, but there could be even better to come. Once you've finished pruning your overloaded files, run a full hard drive defrag for a more general speed boost.

Verdict ratingsratingsratingsratingsratings

A simple but effective way to keep track of your hard drive space. Pity it doesn't work in Windows Vista or 7, though