Macbook Pro fell, Have tried everything I know of...

Hello everyone- I've been perusing the web for a similar situation, and haven't quite found one yet.

My macbook pro fell, resulting in no visible damage, but the system consistently freezes with the "spinning beach ball" anytime I try to open a folder, application, or do anything else...
I hope I haven't overlooked anything obvious, and I can't verbalize how much some other suggestions would be appreciated.

Here's what I've done so far...

(((Macbook pro, 2.8ghz, INtel Core 2 duo, 4GB ram, 1067 Mhz DDr3)))

1- Ran the "Hardware scan" program from the applications startup disk that came with the computer. -No problems found

2- "Zap the PRAM" ("parameter RAM", powered by small battery on motherboard- restart mac, hold Control+option+p+r, let go of keys after a second startup chime) apparently this can fix some opperating problems.

3- Boot the computer up in "Safe boot" mode by holding shift during startup- allows the mac to use only basic functions. From here, I'm able to navigate within the finder well. I then ran the Disk utility to verify and repair disk/ permissions. This was completed and the hardrive appears healthy.

I'm not able to play music or video files in safeboot- and I'm not sure if this is typical...

4- Re-install mac OSX from the startup disk that came with the computer.

x

Whew! Think that's it...

besides starting up in "safe boot", The system still isn't able to do anything besides sping the beach ball cursor. The only other step I know of is to erase the hardrive and start from scratch... I'd rather not do that and have to chase down registrations for a lot of old/obscure programs.
Has anybody heard of cases where there is actually a damaged hardware component that is not exposed during hardware scan?

Any other thoughts for diagnosing what could be the matter would be
excitedly recieved. Thank you!

I hate to say it but it may be a hardware issue if its under Apple Care let a Genius look at it if not take the back off and gently check all your connections. You say it fell
was the computer on when this happened if so I would still suspect the hard drive or maybe your ram got jolted out of the fully seated socket.

Appreciate the good ideas! Last night I removed and re-installed the hard drive and RAM just to be sure that's not the issue. No difference in performance yet.