Unable to enter Vista setup program when certain hard drive plugge

I've had a lot of troubles using the Microsoft Anytime Upgrade service to
upgrade from Business to Ultimate.

The latest problem involves the fact that the Vista install DVD will not
boot to allow me to run a recover on my installation. The DVD loads files,
then the green status bar shows for a little while, and then I get a blank
screen. I've let it set over night (8+ hours) and nothing happens.

I have two SATA hard drives. I've tested both and physically they are fine.
If I unplug one of the SATA drives, then the Vista installation program will
run...but the drive I unplug is the one on which I want to install Vista!

These drives used to be in a RAID, but I had to kill the RAID in order to
install the Anytime Upgrade. I've been running the upgraded Vista Ultimate
for a few weeks now. Tonight I was trying to fix a myriad of problems that
cropped up after the upgrade (like IE constantly asking me to connect to the
Internet, Media Player not connecting to the Internet, and weird freezes when
starting up).

My main goal right now: I want to get the Vista installer to load so I can
repair my installation! I have three Vista DVDs I have used, and they all
act the same. So I know the DVDs are good.

Thanks for any help. Tomorrow morning I'll be calling MS tech support
again, not that they're ever any help...