HELP!!!!!!!

[secretx]

i have a movie on my computer, and im trying to use a shot from it in my sig. but when i press printscreen and i paste it into mspaint, it shows the movie still playing instead of at the single shot that i wanted. ive tried playing the movie in DivX Player, WMP, and ATI File Player (don't ask), and then pressing printscreen. when i paste in PS7, it shows up black where the picture would be. any ideas?