Is my motherboard bad?

I work for a non profit and was recently donated a 15" MacBook Pro - Vers 5,3 - 2.8 Core 2 Duo with the notice that all that needed to be done was a hard drive replacement.

Here is the issues I've discovered:

• The old hard drive boots up but will constantly give me the 'Rainbow Ball' as if it's running background tasks. To get to the desktop takes several minutes and I can't get it to go to Disk Utility or start up in safe mode because it just freezes at that point.
  
• Whenever I try to boot from the restore CD's it just freezes and won't go past the option screen.
  
• When I put in a new blank hard drive, it will boot to a gray screen with a flashing question mark folder and when I hold down 'option' on startup it doesn't detect the new hard drive at all, but will detect the old one.

Could it be that the motherboard is bad? Or does it sound like bad hard drive and the new one I purchased was defective? Any tips would be appreciated, thanks!

Sounds like the notice was right. The reason the new HDD isn't being noticed and the reason you are getting the flashing question mark is because the new HDD has not got an OS installed on it. Keep the new blank HDD in, boot into the restore CD, go to Utilities > Disk Utility, format the drive in the Erase tab to Mac OS Extended. Once done quit Disk Utility and install the OS.

Hope this helps

- Simon

Tried that but it locks up

Thanks for the reply Buzz. I tried that, but whenever I try to boot from the restore CD it just freezes and locks up That's what makes me think it could be a different hardware issue.