Clear out all the hidden garbage
This is most likely the same on XP as well. As for 98 and lower, the files are prolly somewhere, too.
Tonight I was cleaning up both HDD's and realized I was losing a lot of space somewhere. You know all those programs on internet that are suppose to clean up all the downloaded content your computer collects? Ya know, like the pictures, the links, etc.
Bah...why trust a program and go manually do it yourself.
If you're using W2K (or XP), show your hidden files and folders.
Under C:, goto Documents and Settings, <whatever account you use>, Local Settings (this is a hidden folder), Temp, Temporary Internet Files, and then Content.IEx (where x should be the version number of your browser).
Inside that folder are a bunch of folders with alpha names. Enter any of those and delete everything. NOTE: some HTML files won't delete, but they're small enough it doesn't matter. The majority of what you're cleaning is images and videos.
I did this tonight, and found an extra .89 gigs of space on C:. Also note, this folder is different and holds different content then the same Content.IEx folder found in C:\WNNT\Temporary Internet Files\. The files that accumluate are doing so under the folder corresponding to whatever user your logged in as.
On another note, I spent about an hour going through all those images I deleted to see how far back they accumulate. Lemme tell you, I had shit in there from last summer.