Screencapping help

Hello. I've checked the memories, but I can't find the solution to my problem. Whenever I try to screencap from a DVD using Windows Media Player, it just comes out black when I paste it into Photoshop; I can see the toolbar from the program, just not the picture. I tried lowering the acceletation speed to none, but it didn't work. Can you even make screencaps from DVDs using WMP? Or is there a way to take caps other than the PrtSc button? I also have WinDVD, but that's having the same problem (though its a relatively old version, so that might be why...). Is there a way to fix this, or should I just get a new program?