I have recently hooked up two Samsung Syncmaster 2243s to my HP Compaq laptop at work (waiting on an email for the specific model for the Compaq and Nvidia Quadro video card). Unfortunately, the second monitor says "Check Signal Cable" and will not display anything. Here's how I have it set up: The first monitor is hooked up to the laptop on the VGA port and works fine. I have used extended display with my laptop screen and Syncmaster with no trouble. I hooked up the second monitor to the HDMI port in my laptop with a DVI-HDMI cable. At no point (eg. when restarting) does the monitor show anything but "Check Signal Cable". I have updated my drivers (windows and Nvidia) and tried removing my display adapter and restarting, forcing the computer to reinstall the drivers. I have rebooted with the second monitor attached and unatatched with no luck. The key point is that the computer recognizes the second monitor (with the Nvidia control panel I can turn off the laptop screen and set both monitors as my extended display - second monitor still says no signal although the first monitor, which works, behaves as if it were part of an extended monitor). Further, the second monitor works normally, as it was used on a previous laptop via VGA. What could cause the "no signal cable"? I did buy a second DVI-HDMI cable with the same result. Any help would be most appreciated.