Heya,
i have a problem with my current Win 7 system on my laptop.

I have it connected to a HDTV and usually i keep the laptop closed, but sometimes i need to open it (so it won't overheat when gaming). But when i open it, windows switches the main screen back to my laptop screen instead of keeping it on the HDTV.

I tried changing the energyoptions but that only works for closing the laptop, not for opening it.

Worked fine under Vista before.

Any ideas how to change this?

Have you gone into the settings to check how Windows and/or your video driver is working with multiple monitor setup? Perhaps it is currently set to work on only one display instead of two.

At least my Laptop disconnects its own screen when I close it, and reconnects it when I open it. This also has annoying effects when a TV or second monitor is plugged in and this may be also the reason for your problem.
Maybe you won't have a problem if you just turn on "clone"?

Is your HDTV set to be the primary screen?

@RealSerious3D, it is set to only one but that's what i need. I only want to display it on my HDTV and deactivate the laptop screen, no matter if open or closed.

@Lukas if i use clone, i can't change the resolution to fit my HDTV. It does disconnect it's screen when i close it, but i don't want it to connect it when i open again

@Uhrwerk, yes i've set it as primary screen but it still switches back.

It technically would work if i choose "extend" to second monitor and keep the HDTV as primary, but that is annoying since i can go out of my display with the mouse cursor (onto the laptop screen)

Kinda weird it doesn't work "easily". I don't think i had troubles with that on Vista so i doubt they "removed" a feature? Should work somehow...

Does your notebook have some special function keys (FN + some key) where you can toggle between build-in-display, build-in-display + external, only external?
Or is that the function you already used?

what video card do you have? i ask because all of the drivers that came out in the last two years for the nvidia 8xxx series to the 98xx series sometimes have issues with hd connections. for instance right now i have to use a very old driver that isnt even for my card just to get my monitor to work.

If you simply duplicate the displays, then you should be fine. You will get a display on each, but it will remain on your HDTV once the lid of your laptop is closed. Or you should be able to select only one monitor and choose the HDTV for the primary (or only) monitor.

@Xarthor, the FN keys won't change much in this case, i can toggle through it, but still after closing/opening, it would change again so i have to re-toggle the screens.

@lostclimate i actually do have a GeForce card but a 240M. Hm not sure if i had the newest drivers on my Vista system which i had till last week, but maybe i should give older drivers a try and see if that is the same problem.

@RealSerious3D, well yeah technically i could use that and it wouldn't switch the screens, but the problem is that my laptop can only display 1600x900, where my HDTV has the full 1920x1080, so if i clone the image, i can't have full HD on my HDTV.

There are some monitor managing programs like UltraMon, I don't know if they can fix your issues, though.