This auctually happend about a week ago, I just thought Id post it here.
So, I was minding my own buisness, when I leaned back in my nice chair. The chair fell backwards (which has happened to me before).
The legs of the chair got caught under my computer desk, with me still in the chair, the desk began to rise. as I tried to get out of the chair everything was falling on me, then I watched as my computer case fell crashing to the ground, still running I pulled the plug on it. (I was still in the chair). My new $300 moniter was about to fall on me as well, luckily I got it to stay stable.
The computer case fell off the desk a good 3-4 feet, the front panel flew off, cd-rom drive popped out (I didnt screw it down), all the cables on the back came loose (And if I would have tightened everything like your supposed too, the moniter would have fell over.)
Now, I assumed the computer was screwed and it was over, Anyways I did a quick check, all of the cards came out of thier slots slightly, I pushed them back in.
I put the computer back on the desk, plugged her in and turned her on.
It post.
It booted into windows.
It worked like nothing happened at all.
I only had one issue since, which the video card heatsink fan wasnt spinning, but other than that the system works fine.
I love my computer. Its crash proof.

(Literally).
It still runs rock solid too.