if you already have the video on dvd and you're playing it on windvd, then what are you trying to capture? and what format are you trying to capture it to?
auto gordian knot will convert dvd to avi as long as the separate PGCs are ripped in IFO mode with a program like dvd decrypter.
for other options you can do a search for "DVD to ___" (whatever format you're trying to end up with.
I'm not sure I'm clear on what you're trying to do, but if you have a dvd and you want to end up with a specific type of file of that video on your computer then you shouldn't be looking to capture, you should be looking to convert.