I need to uninstall and reinstall iTunes (it won't let me update). So, how do I copy or back up my iTunes library of over 1,500 songs? Can I use a Flash Drive to do so?

I need to uninstall and reinstall iTunes (it won't let me update). I have IE 8 on Windows XP, and iTunes 10 something. In my Program files list I see iTunes and iTunes (2) and even iPod and iPod (2) where a tech had to back up and do this for me before. I'm just trying to fix it all. I keep getting the "The feature you are trying to use is on a network resource that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'iTunes.msi' in the box below." I can even run a search and find the folder, but it gives me the same error message. I was planning on using the Microsoft Fix-It tool to help uninstall then Reinstall iTunes. But I need to backup my library. So, how do I copy or back up my iTunes library of over 1,500 songs? Can I copy the folder to desktop or can I use a Flash Drive to backup my music? I don't want to do anything until I know for sure how I can backup my songs, and then reinstall them into iTunes. Thanks for any help.