Sounds like a tough one... but some other ideas... I've had issues with my install and this is what I've had to do to get it to install.
1) make sure the BIOS is the latest version
2) remove all but one stick of my RAM (leaving a 1GB stick)
3) unplug all extra HDDs (leaving only my CD-Rom and the HDD I'm installing too)
...if possible for you to do, I would recommend making sure your video card's BIOS is updated as well.
I then format my HDD and then I can install Vista, after the install I apply the 4GB patch ASAP, I then reinstall my HDDs.... Vista will still hang on a black screen on every restart for me until I've installed my motherboard and video card drivers.... after that then I reinstall my 4GB RAM and everything works as it should... but it's a pain.
Want funny?.... Vista didn't have these problems installing the first 5 times... but now it does with no hardware change... figure that one out.