Okay , Here is the story.
This PC is about 1 year old now , and recently i have been having troubles with DirectX
I can start up a game and when i close it down to start up another game i get an error.
Also my WMP/VLC & Classic Media Player , stay black when i want to watch a movie/video when this happens.
And in order to fix this i have to reboot the whole PC.
EDIT : If i wait to long with starting up a game after booting up, 30 minutes or so it also happens.