If you have access to one, see if you can borrow a monitor with DVI input, and plug it in. Then you'l know if its the adaptor or the output itself thats not working
I've found out why it doesnt work! The video card only has one RAMDAC so it can't convert the signal for the screeen to analogue which means that even a DVI-VGA adapter won't change the signal. Only monitors that use a digital signal will work!