How to replay videos while having a program run on fullscreen?

I cant seem to have my videos replayed if Im running another full screen program(like HL2*Game.) Ive used both WMP and MPC and set them on Replay Forever/Repeat# times but they're only played once and they stop. I hate having alt-tab just so i can replay the video manually. Does anyone know how i can fix this? I don't have a problem with audio files but just video files(WMV,MKV, etc.) I want to be able to replay videos while having another program run at FS, Im trying to avoid having to rip the audio off the video since the file is a MKV and that would mean i would have to convert it(degrade quality) then rip it off the avi/wmv file.