The windows xp C:\Documents and Settings\(the user name)\Local Settings\Temp folder
 

It's a couple of gigabytes for me, and I was wondering, since it's a "temporary" folder, are all the files in there necessary or is it okay if I delete everything in the folder? Are some of the files essential? Or do I just leave it alone?

Thanks.

You can safely delete anything in that folder, just don't delete the folder itself.

I've deleted stuff in there sometimes, and I think it's mostly Okay, but hedge your bets by deleting the older/larger stuff first.

You might also try right-clicking on your drive, selecting Properties, and pushing the Disk cleanup button. I wouldn't be surprised if that cleans up the Temp folders either.

What kinds of things does disk cleanup delete? It doesn't delete programs that haven't been used in a while, does it? In other words, is it "safe" to do?

It'll clear out temporary folders (like windows ones and things used for internet browsing in IE) and it'll also compress files which haven't been used in a long time on your harddrive (I think the default is three months). Compressing them just makes it take a little longer to access the file, though if you haven't touched the file in over a month it probably doesn't matter a whole lot.