Thanks for that bit.
Wish I
wouldn't have listened to that before I tried to get my MBA drive to run DVD Player on the MBP.
Only had to reload SL twice though.
Drag & drop software bits from another product can certainly corrupt your OS.
If you're using the operating system that first came with a Mac, it probably has modifications that allow the OS to run on that hardware. This is regardless of whether it's a MacBook Air, an iMac, etc...
When you use the Migration Assistant to transfer data from an old Mac to a new Mac, it intelligently will not replace a new or customized version of an Apple application with an old version. I realize that the original poster did not use Migration Assistant. Unless the original poster transferred bits from the /System/ folder, there's not a piece of software that's causing this symptom.
Transferring an application from one Mac to another will not damage either Mac's operating system.
When not using one of those "Apple-custom builds" of Mac OS X, the same hard drive will properly boot ANY Mac. For example, right now, a 10.6.1 drive that you create will boot a Mac Pro, a MacBook Air a previous gen iMac, a previous gen Mac mini, any MacBook Pro. It will boot any other Intel Mac that was released before last Tuesday. Every applicationincluding DVD Playerwill work properly. You will experience strange behaviour if you try to boot one of the newly released Macs with a standard 10.6.1 drive, even though the OS version may appear to be the same. Once 10.6.2 comes out for everyone, this drive will boot every Intel Mac, including the ones just released.
NC MacGuy, it sounds like when you were having DVD Player trouble, one of your computers may have been using one of those factory custom OS builds.
--
It's possible that the original poster's trouble is caused by:
Bad logic board RAM. This isn't common, but it can happen. If this is the case, the computer should be replaced or repaired.
A corrupt preference file. If this is the case, a competent Apple Store Genius will quickly identify the problem.
Since the original poster has already reinstalled Snow Leopard twice, we can be somewhat confident that the System folder and bundled applications are the proper versions.