My hunch was correct!!

When I got home & hit shut down, it did not shut down!! Same issue. The Operating System would shut down and conclude, leaving a black screen - but the PC wouldn't power off. I had to manually hold down the Power button to turn the system off. This was on BIOS 0803.

The only time my system completely shuts down is after the first Boot Up after a BIOS Flash (Clearing CMOS). Whether I'm on Stock (Defaults) or OC ... whether I'm on 0803 or 1403. It's the exact same behavior.

This leads me to believe, as far as I can establish at this point, my problem has nothing to do with truehighroller's bug ... nor does my problem seems to have anything to do with the BIOS. I'm getting identical results on 0803 & 1403.

I know for a fact that no hardware (or BIOS) changes were made to my system anywhere around when the Shut Down problem started - however - I keep updating software and installing newer applications. At this point I'm strongly believing that my Shut Down woes are a software complication. In most likelihood, I'm going to format my hard drive & reinstall Vista. I'm going to stay on 1403 for now and see how I make out with a fresh reinstall of Vista.