Vista - Vista x64 Media Center Black screen

I've got Vista Media Center (x64 Ultimate) installed on my machine, and it works great. Specs as follows:

Asus A8N-SLI-Deluxe
Athlon64 3800+
2Gig Ram
7600 GT
74GB WD Raptor on Nvidia slot as IDE

Now, I went and purchased another license for my Media Center, it was XPMCE. The specs follow:

MSI K8N Neo4 Platinum BIOS revision 1.D
Athlon 3400+
6600GT Latest 64bit release drivers
2Gig Ram
250GB WD SATA on the Nvidia controller as IDE

The MSI platform installs perfectly and does everything but run Media Center. I can run it, but it shows up as a black screen. I can hear the startup sound though. I've gone through numerous reinstalls, but can't get past this issue. Anyone know of a fix?

Have you tried swapping the video cards to see if it makes a difference (assuming they're both of the same type)?

I've tried it with a 6600gt, 7600gt, and an 8400gs. I don't have any other cards or motherboards to attempt it on. I've verified this with another machine that is based off the same K8N Neo4 platform.

I've also verified this same behaviour with the Geforce driver releases of 175, 169, and 163.