I'm driving two external monitors (or trying to) (DELL 2408WFP and DELLU2711) on an XPS17 L702X. Sometimes only one comes on. Both come on when Microsoft executes updates and reboots. Only one comes on when I reboot (DELL U2711). When both are on, the 2804 is driven by a NVIDIA GeForce GT555M; the other by the Intel Graphics card. The 2804 is not seen by the system...does not discover it. Any ideas?