I had a weird one with cat5 hdmi baluns, if the hdmi lead was plugged in the PC wouldn't boot - the hdmi balun was causing the motherboard status light to come on too even if the PC power was off, still haven't fixed that (h51 chipset) AMD zacate board works fine...
Have you tried turning off Hardware Acceleration ?
You should try another projector to test if the problem is because your projector.
Just an update for everyone/anyone who's interested.
I've been faffing around with this computer, and have managed to get it working on my test projector by using Win+P.
I'm not going to bother with trying to get it to auto-project as it's in a Nursery class and I doubt the teachers will be happy with the pupils turning it on to play with it all the time. [Win+P is the new "CTRL+ALT+DEL to login"]
So, I've just had to go in there again...
The computer is now refusing to boot properly when connected to the projector.
It works perfectly fine with a monitor and with the VGA cable pulled.
At the moment they're having to boot the computer with the cable pulled out and then attach it after it beeps a couple of times...
Does anyone have any ideas why this isn't working properly?