Have a Dell Precision T1650 with (1) AMD FirePro 2270 running 4 DVI monitors. One 2270 card with one high density plug split out to 4 DVI connectors. Monitors #3 & #4 have quit overnight after 4 years. Literature says the 2270 can only run 2 monitors where this one is doing 4. Any ideas how to get the 2 monitors back operating?