Lubuntu is another lightweight OS. I have a pretty descent Dell Optiplex SX260 with a Pentium 4 and 1gig of ram but Ubuntu nor Xubuntu would run good. In fact, web browsing would crash them. It would lock up and I was forced to hard reset.
Official site is here
http://lubuntu.net/Lubuntu is running on the yet to be release Ubuntu Lucid 10.4 so it is still in Alpha. I used
http://unetbootin.sourceforge.net/ to burn the ISO to a usb drive and then installed it on the HD of this Dell.
I really think the hard drive on this Dell is the cause for the crashes but have not invested on a new one just yet.
Anyway, the installion was a breeze and it seems pretty snappy! So give it a try.
