I have Windows 2000, can I put XP on my computer without erasing all the data I've already got?

Yes, but I'd advise against it. It's better to do a "clean install" and clean out all the cruft that has built up from all the applications that you have installed.

Save all your data to CDs and start from scratch. You'll feel better in the end.

I have Windows 2000, can I put XP on my computer without erasing all the data I've already got? ex. songs?windows installer

yes. but have someone that knows what their doing do it.

I have Windows 2000, can I put XP on my computer without erasing all the data I've already got? ex. songs?microsoft vista internet explorer

yeh it will, but save all your songs etc to a memory stick or other storage media and then pop them back on!
Yes there is a way to have both on your computer at the same time. On my computer I did the same thing. It should be in the options when you install it but I might be wrong. Just know that it is possible and when it starts up it will show both and you have 5 seconds to choose which you want to start up.
Yes, installing a new version of Windows should only change the files in the Windows directory, not other folders. However, it is still a good idea to create a backup, in case something goes wrong.

Although, you should make sure you have at least 512MB RAM before you upgrade to XP, it is a big memory hog. A good RAM manufacturer is Crucial.
Yes you can. When you put the XP CD into your CD-Rom, it will walk your through the installation. It's very easy and simple although it takes several minutes.
The best way is to install two separate OSs on two separate drives. Make a slave drive and a primary. You could also partition if you have one HD but make sure you have enough memory. This is something a typical user should not attempt unless you are willing to lose all the info from your first OS (if you screw up). The fact that you asked the question means you should probably get an expert to do it (no offense).

There are, however, a lot of tutorials on the web for this sort of thing. Do a search and stick with techimo, cnet, computing.net, and softwaretipsandtricks.com for reputable guides.
Trik turner owns you little kid. You have no respect.