iTunes trouble

[I have Windows]
Some of you know I just bought an iPod. Now, I obviously installed iTunes. When I click on the shortcut, I get a loading cursor. A few seconds later, the cursor changes back to the standard one. THen, nothing happens. Sure, my computer slows down, and every program I have running freezes. When I hit Control + Alt + Delete, and go to Processes, there is an iTunes one. When I reboot the computer, the same thing happens. Sometimes, if I shut the computer down for a while, and turn it back on, iTunes works. So I pop in a CD, and it freezes. Then, I restart the computer with the CD in it, and when it comes back, it freezes again.

I have Windows XP Pro.
RAM 512mb and Intel P4 3.0ghz (don’t know if you need to know that)

I used the iTunes that came with the CD I got with the iPod, and downloaded it online from iTunes.com, with basically the same problem.

What do I do?