WMP Issues?

I've had a Windows XP operating system before and I've never had any codec issues but I got this computer a year ago and it has serious issues with video playback no matter if I use WMP or Real Player. The video is choppy and the video goes slower than the audio. Also, if I right click on a video file, my screen will flash black for a few seconds then return to normal. I've tried updating the codecs before and nothing, I use several different media players to play all my video files which is so frustrating trying to remember which player plays which video. Does anyone know what could be causing this? Any help would be awesome.