I went through this issue a few years ago (with an ATI 9600 no less).
I'll tell you my conclusion first: I seperated my media display computers from the control computers....
You're not there yet, so I'll tell you the two ways I solved it before dedicating machines to control:
1) Make your secondary monitor the touchscreen. Mainlobby just needs a few x / y paameters to get moved over to the second display, and you can keep your primary display for movies, PMM, or games, all of which will have issues on the secondary monitor. If you are having touchscreen tracking issues with it as the secondary, make sure you have the latest drivers, as most support dual monitors now.
2) Will you need to run the touchscreen while PMM & a movie are playing? If not, you can write a script that will either swap screen 1 & 2 (primary secondary to secondary primary) so PMM will run on the TV (which would be primary for a bit), or make the TV primary with no secondary, effectively turning off the touchscreen while you are watching PMM.
3) download Hydravision from the ATI website. t's a dual-monitor support app that can (among other things) remember which screen to launch a program on.
or my favorite,
4) use Ultramon. This handy dandy little ap has shortcuts which will designate what monitor an applicaiton will run on (like hydravision), display profiles which let you dynamically switch your monitors around (like #2 above), and hotkeys to move applicaitons among monitors in realtime.
It could also put your touchscreen into screensaver mode while a movie runs on a second monitor. It's pretty slick.
Alex D Zoghlin