I have a Sony flatscreen TV that has a VGA hookup and an ATI card and recently hooked a laptop up to it. Initially it just ran dual desktops instead of one being an extended desktop and when I would play a video file, it would play it on the TV while the laptops monitor would remain normal. I believe this is Overlay mode in the ATI settings, but I did something to change these settings and for some reason after messing around with them for quite some time, I can't get them to get back to that mode.

All I want to do is get them to run the desktop at the same time (instead of one being an extension) and for that feature of when a video file is being played, it plays on the TV.

You need to make the TV your primary monitor. Video will only play on the primary monitor. How to do that depends on your drivers. The only PC I have with ATI video is my laptop, if you haven't figured it out by the time I get home I'll post a picture.

Turn off hardware acceleration (or if possible, turn it on OpenGL) in the video player, and it will appear on either screen without issue.

Weird. On my nVidia card, it automatically switches monitors when > 50% of the player window is moved to the other monitor.

Turning off HW accel, as CM said, makes it possible for me to have the window straddle both monitors. It would fix your problem too.

(Thanks for the responses)

Well the video will play on either screen, but originally when I hooked it up, the TV didn't act as an extension of the laptops monitor and ran the desktop the same, but when I would play a video on windows media players, only the video would be displayed on the TV and I could do other things on my laptop with the video playing and only the playback would show on the TV. I believe this is "overlay" mode in the ATI settings, but I can't do anything with it right now for some reason. I'll try messing with hardware acceleration though.

Ah, I fixed it.

Apparently I was looking to put it back into "clone mode" and I eventually figured it out. Thanks a lot for your help though guys.