If you just wish to play individual .VOB files...try renaming
them to .MPG and you can play them with Windows Media
Player. If you wish to play the DVD as it plays in a DVD Player...
see the following...
First...you would copy the VIDEO_TS folder from the DVD
to a folder on your hard drive.
If Windows Media Player will play regular DVDs...you could
open it and go to...File / Open...navigate to the VIDEO_TS
folder and when you open it select all the files inside...
(Ctrl+A should select all files) with all files selected...left
click the 'Open' button and the DVD should launch in Windows
Media Player.
Also...as an alternative...
If you download and install the freeware VLC Media Player...
you can right click a VIDEO_TS folder and from the menu...
choose..."Play with VLC Media Player".
(FWIW...it's always a good idea to create a System
Restore point before installing software or updates)
VLC Media Player
http://www.filehippo.com/download_vlc/
(runs on XP/Vista/7)