I don't understand what you mean by you can't find the drivers you need. Have you already installed XP and are now just trying to get devices to work? If not how do you know you don't have the drivers?
There is a good chance that your original Vista and Ubuntu are still there, maybe just your boot loader was messed up. I would try to save them, you can probably just reinstall the boot loader.
Download a different live CD, Ubuntu works fine. Boot to it and you should be able to see what is on your partitions. If your files are still there it should just be a matter of reinstalling the boot loader. I'm going to assume your computer came with Vista, and that you then installed Ubuntu afterwards, and that you were using grub as a boot loader, is that correct? If it is a Google search for 'reinstall grub' should give you the help you need. This site looks like a similar situation:
http://www.howtogeek.com/howto/ubuntu/reinstall-ubuntu-grub-bootloader-after-windows-wipes-it-out/
If you really want to install XP then my question would be what type of XP disc do you have? Is it a full install CD, an upgrade CD, or one of those discs that come with new computers that are pretty much worthless? If you have a full install CD installing XP is easy, just put it in and follow the directions. It should have enough drivers to get everything working on a basic level. You will probably have to install drivers for your video card and network card. If you need drivers for the network card your internet won't work until you do, so it's very helpful if you have a second computer you can use to download stuff.
Please give some more info on the specifics of your situation, as well as your expertise (I'm assuming you did the Ubuntu install), and I'll be happy to give more help if you need it.