does anyone know how to open a video_TS.IFO file???

VIDEO_TS.IFO is a video transport stream info file from a DVD. It can be read by certain open-source tools that can disect DVD files, but the info file basically contains nothing more than meta-data about the contents of other files on the DVD (it identifies the region of the disc, which file contains the entry point for playback, the offset for start, the video standard used, etc.). Mostly, it's not very informative if you don't have the rest of the files that go with it.

Here's some info on the file, if you want: http://www.dvd-replica.com/DVD/data-3.php

If you download dvdauthor, it contains code sections for reading and writing the .IFO file.

A VIDEO_TS folder is what holds the content of a movie's video and audio on a DVD.

The file you have is a ripped copy of that folder. The free VLC Player can supposedly run it.