Windows XP includes a DVD exe program. Go to C:\Windows\system32 and look for dvdplay.exe put a shortcut to it on your desktop. You may need to download some codecs to see every video format.
Go to
http://www.k-litecodecpack.com and download the basic or standard
You may need to launch your desktop shortcut first then insert the DVD to play it. I think you'll find with the proper codecs, it will work better than any of the other software programs you add to the computer.