Problems setting up Multi monitors..

[AJ!]

Hey peeps

Gota Problem setting up 2 monitors at the mo....

The computer uses two graphics cards and i have plugged both monitors into the main card. when i turn the computer on both the monitors show the loading screen but when the desktop comes up the second monitor turns off.

I have gone into Display properties and the computer shows up 3 different monitors... The main dell monitor, a Plug and play monitor and a Default monitor.

The problem i have is when i try to activate these (extend desktop onto this monitor) it doesnt do anything and the second monitor wont pick up a signal...