Ubuntu :: Fresh Install Of 9.1 Really Slow And Unusable

I have an old Dell desktop that normally runs XP. It has 512mb of ram and I think its a Pentium processor. From what I understood Linux is a simpler, and more stable and efficient OS so I figured I'd give it a shot. First I tried the Wubi installer and got nothing but error messages after the install and it kept freezing and eventually just wouldn't boot at all. So then I tried the full install from disc. Better at first. I soon discovered all the customizable themes and went a little nuts trying to make one user exactly like W7 and the other exactly like OSX leapord just for fun.

I noticed significant slow downs and after some research I came to find that it was taxing my old graphics card. So I setup a user with no changes, still really slow. Then I deleted and reinstalled and I'm now using the bare bones UI. Its still really, really slow. I get lots of mouse drag and just now it took about 7 seconds for the applications window to drop down and 35 seconds to open the home folder. Also about 10 seconds for right click window to drop down.

I'm trying and I really want to like Ubuntu but as of now I'm finding it unusable for even the most basic of computing. I realize my computer is old but xp still runs like gangbusters. So maybe Ubuntu is designed for more modern hardware and more ram, am I screwed? I was looking forward to playing around really customizing my GUI but more importantly I was planning on putting on my girlfriends laptop with similar specs. Her computer needs a reformat but she doesn't have the XP disc. As it stands her XP is still much more usable even with all the viruses then Linux is as a fresh install on my desktop. I don't want to delete xp and end up with a slower linux.