the free fall sensor didn't sense anything

Heh. I see you do the same tests that I do

 

If your HDD is not damaged then free fall sensor worked.
All it does it that the head moves away from the platter so that the head don't crash on the platter(s).

If you have Vista, then the kernal is on your RAM... if teh HDD is not in use, the OS should not shut-down, freeze or BSOD on you. Don't beleive me?
Play Winamp Internet Radio... wait until your HDD has no activity, and pull your HDD while the system is running. Your system will still work without an HDD. Mouse will move, music will continue to play. If you run applications from the Start menu, nothing will happen, of course, but the task will be queued. Once you put back the HDD, the HDD will spin back up, The SATA controller will detect if the HDD is ok, then Windows will sync it self... once done, every task you executed will be executed in order. Pretty cool stuff no?

How do I know this? Simple... while I dusting off the inside of my running desktop comp, I accidentally unplug my SATA cable of my HDD. Once this even occurred I started to do some test on a test HDD with Vista on it.

 

LMAO! that put me to the ground.

yeah, I was expecting it to shut down but only after completing windows update. LOL

well, cool stuff then. I am glad to hear that the extra bucks were worth something.