No image on Samsung 213T

I'm trying to use my Samsung 21" flat panel display with my 8790 for the first time. When I first hooked it up and configured the laptop for dual displays, the image on the 213T was unstable, flickering as if the refresh rate was not properly set. After a few minutes I couldn't get any image on it. I downloaded and installed the Hydravision utility from ATI.com and the image came back, but again it was very unstable and eventually there was no image at all, like before, whether I extended my desktop to the external display or I used it as my primary display. I had a Samsung 19" before this and it worked fine with the 8790.

When I hit the Source button on the LCD it shows me "Analog" with no picture, and then it automatically switches to "Digital" and then the display goes blank. When I wait long enough for the LCD to power down automatically (based on the settings in the Windows Power Options control panel), and I hit a key or move the mouse, the power light on the LCD comes back on like it should when it wakes up, but there is still no image.

I tried to go with the D-Sub cable but as my luck would have it, both ends of the cable are male, while the laptop is male and the monitor is female.

I can't figure out why I can't get an image via DVI. I've installed the latest drivers from both Samsung and ATI. Have I missed something?

Of course, right after that post I figured out that I was using the DVI cable from the 19" monitor (which was destroyed in a tragic, intertia-related incident), so I swapped it for the one that came with the 21", which is a slightly heavier gauge and whose ferrite cores are slightly larger. I rebooted and, with Hydravision installed, the Windows logon screen spanned both monitors, which was kinda cool. But hope for dual-monitor gaming is fading quickly because now I'm back to no image on the LCD, with the correct cable. I don't even get the OSD menus on the Samsung, and occasionally I'll get the monitor's little hardware screensaver with the Samsung logo, and below that it says "Check Signal Cable". Both ends of the cable are firmly seated and screwed in, and I know the desktop is in fact extended to the second monitor because my mouse pointer doesn't stop at the edge of the laptop display.

*boggle*