Please try adding the /close parameter to the mix as well. Report back. If not then we'll meet in chat and try to troubleshoot in real-time. i.e. "C:\Programs\K-Lite Codec Pack\Media Player Classic\mpc-hc.exe" [VIDEO] /fullscreen /play /close GameEx should have no trouble launching this at all. I've used this player on my HTPC previously from the command-line and since that's how GameEx works, it shouldn't have any problems. There is also a setting in the player that may be causing this behavior.