Vista - Cannot extend desktop to second monitor

I am trying to extend my desktop to a second, identical monitor.

I have a new Dell Studio desktop running Vista Home Premium X64, with an ATI Radeon 3450 display adapter. I have two identical 19" flat, widescreen LCD monitors connected to the display card using an SVGA "Y" adapter. In the ATI Catalyst Control Center, the second monitor is not enabled (it is greyed out). When I right-click on the number 2 monitor and select "Enable" the number 2 monitor graphic lights up for about 3 seconds, and then goes grey again. The monitors remain clones of each other. I have tried installing an updated driver from AMD for the card, but to no avail. The same problem occurs when I try to extend the desktop using the Windows control panel display properties. The monitors remain cloned.

Is this a Vista problem, or do I need another display adapter?

This is driving me nuts.

It may be a problem with the y connector. Have you tried 2 separate cables?

Correct. He needs to connect the second monitor to the second DVI port on the video card.

thanks much for the help. I picked up a VGA to DVI adapter, connected the second monitor to the DVI port on the video card, and all is working great now. Life is good.

Thanks again.

Jim