Little as I care for troubleshooting Windows issues, reader Don Phillips writes in with a Windows concern that’s right up my alley. We pens:
I have one of the first Mac Pros and have two monitors plugged into it. The ATI Radeon HD 2600 XT graphics card in it was producing weird lines on my screen so I replaced the card with the Nvidia GeForce 8800 GT that Apple started selling. Video looks great on my Mac but now I’ve got a problem with Windows. I’ve installed Vista under Boot Camp and when I boot into Vista I can use only one of my monitors—the other stays black. Vista’s Displays Settings control panel is no help because it tells me I have a generic VGA adapter. Have you ever heard of this problem?
Heard of it?! Dude, I’ve lived it!
I too was unhappy with the performance of my Mac Pro’s graphics card so, like you, I took the plunge and paid Apple $280 for the NVIDIA GeForce 8800 GT (early 2008) Graphics Upgrade Kit for Mac Pro. Installation was as easy as can be but, as with your Mac, when I booted into Vista running under Boot Camp, my Apple 20-inch display appeared as expected but the Dell 20-inch display next to it remained dark
The solution is to remember where you are. Your Mac is now, for all intents and purposes, a Windows PC. In order for it to produce the dual-monitor goodness you’re looking for, it needs a Vista driver specifically made for that card rather than the generic (and unworthy) driver supplied by Microsoft.
You can find that driver on Nvidia’s website. When you reach that page, click the Drivers and Downloads tab and download the Windows Vista 32-bit version of the driver. Install it, restart your Mac (booting again into Boot Camp, natch), and then right-click on the Vista desktop and choose NVIDIA Control Panel from the contextual menu. In the window that appears choose the Set Up Multiple Displays entry and in the resulting pane, choose the option you want (choose the Configured Independently From Each Other—Dualview option to extend the Vista desktop across the two monitors).