capturing still image freeze frame from MPEG ?

[preventec47]

I have a video that I think is MPEG format but actually is
a file that ends in .VOB and my favorite still image capture program
that captures snapshot screen images to JPG files called IRFANVIEW
does not capture the video when it is running. All it captures is
black blank screen.
The only reason I think the .VOB file might be MPEG is because
the Windows Explorer disk manager labels the file as a MPEG file
but it might not be a MPEG file format..

I just want to capture some freeze frames so that I can study
the detail of the airplane better and I can do that best in JPG format.

On my old machine, which was WIN98, I had a screen capture
program that seemed to work ok on these VOB files but I do not
remember what program it was.

I realize that here most people interpret screen capture as capturing
video in video formats so I hope the still image stuff is not too
primitive. The smallest sample video I have is 50,000kb or
I guess 50 mb. I have a reasonably fast connection I think if
anyone wants be to send a copy to play with.


Thanks for suggestions in advance.
Scott in Atlanta