Black screen during Windows install

Hello,

I have a late 2012 27-inch iMac with the GeForce 680MX 2GB graphics card. I'm trying to install Windows 7 or Windows 8 using Boot Camp, but neither works.

In either case, I can use the Boot Camp Assistant to create a bootable USB install disk, download the latest Windows support software from Apple, and partition the drive to allocate space for the Windows installation.

As soon as I partition the drive, the iMac restarts and tries to boot into Windows. But the only thing I ever see is a black screen (no blinking cursor), no matter how long I wait.

This seems like the exact same issue that plagued the late-2009/mid-2010 iMacs,

http://support.apple.com/kb/TS3173

In other words, it looks like the drivers included with the default Windows install disk don't work on the late 2012 iMac, at least not when configured with the 680MX.

Since this looks like the old problem but Apple doesn't appear to have provided drivers for the new iMac yet (the older iMacs above used ATI graphics, not NVIDIA), I tried to add the latest NVIDIA notebook graphics card drivers to the Windows install disk using the directions here,

http://superuser.com/questions/501812/corrupt-graphics-during-windows-8-installa tion

In particular, I used these drivers,

http://www.geforce.com/drivers/results/55125

They're not explicitly supporting the 680MX (I couldn't find any drivers for it in NVIDIA's website) but they do support the 680M and a whole slew of other cards. Thought it was worth a try.

Anyway, that didn't do the trick. Still the black screen for me.

Any ideas? Have others had this issue with the new iMacs?

Thanks