Well, at some point, you have no choice other than to kill it.  Seven hours is more than fair.  Down it and hope for the best - any damage has already occurred by now.  I'm sure you know that you can't brick the "box" by shutting Windows down early ... you can damage Windows files and/or the Windows file system, but you cannot brick the actual server ... just wanted you to be clear on that.  If Windows doesn't come up, then do a Startup Repair and the usual OS recovery/repair methods.  If Windows does come up, consider yourself lucky ... and you might consider running a CHKDSK /R and/or SFC /SCANNOW to fix any risidual issues.  "Most" often when this happens, everything is ok, it's just that Windows fails to shutdown for some reason, which occurs after the "important" stuff.
R720xd (with MS Server 2008 Datacenter pre-installed) was received and installed yesterday without issues.  MS Patches were downloaded via Windows Update and installed.  Server was powered down for the evening (patches we're applied during shutdown processes).  Server was powered up early next AM and has been sitting with the "Preparing to Configure Windows .  Do not turn off your computer" for 7+ Hours.  "Wheel is Spinning" and Drive activity Leds are randomly flashing (all 24 drives). Don't want to brick the box by powering down, but can't leave in this state indefinitiely.  Any suggested actions?
R720xd Hangs after initial install and application of MS Server 2008 Datacenter 
Patches