removed the bottom of my case to fit the cards

switched on, installed catalyst, rebooted, done.
And yes I have two screens and you need "two screens"
If you put 2 geforce in 1 machine it detects both even with only one connected to a screen.
With different drivers it does not recognize the second card as active without a screen.
However, all you need is do connect a dummy dvi so windows thinks there is a screen:
http://www.google.com/search?source=ig& ... =&aql=&oq=
hth