Hey all! I'm not sure quite where to put this thread, so hopefully this is the right spot. It could be the video card, motherboard, Win7, or something else acting up.
I recently put together a new computer and installed Windows 7. I used two monitors on my old computer (XP), the regular monitor hooked up to the DVI port and my TV hooked up to the VGA port on my video card. I used the same card on my new machine at first, and recently replaced it with a newer Nvidia 460 card. I've had this same trouble on both cards, however. When I have both the monitor and tv hooked up, occasionally, the monitor (the primary display) will lose it's signal and power down, and the desktop will transfer over to the tv. After a few seconds, the monitor will power back on and the video will transfer back, with all the windows at the changed resolution of the tv (it's an older HD tv, and the hdmi port is busted on it). This *only* happens when I have the vga plugged in, though. It's never happened after I unplug the vga cord from the video card, and it never happened over the past few years when I've had the other computer. Any ideas?
Oh, there was one more thing. I've now noticed that when I have the TV plugged in, when I reboot, the bios and loading information displays on the TV until Windows starts loading, and then it switches to the monitor. I've looked around my BIOS, but I don't see anything that might be causing this, although I do admit I'm a bit of a noob.
When you right click on your desktop choose Personalize, then choose Display Settings, you will notice there are two monitor - Pressing identify will give you the primary monitor which is your DVI(no.1) and second is your VGA (no. 2). The VGA is 800x600 pixels or below for the TV this is easier to display than the high resolution - DVI. Try to set your primary to DVI and disconnect the VGA when booting up.
@dEAne - Yep, the monitor is set as primary display, and the tv is #2. I've tried having the tv plugged in when I start the computer up and I've tried plugging it in while the computer was on, same problem. It seems like now I can't keep the tv plugged in at all, within minutes the monitor loses the signal.