hard drive format problem

I recently bought 2 western digital 320 gb harddrives. After installing in my macbook pros
the computer will not recognize them thus cannot load OS 10.6
I powered them up, read them through the usb port onto the desktop of my operating mac.
once in disc utility I erased all info and loaded the OS from my computer onto the hard drives.
I set both up as extended(journaled) The load went fine and info was installed.
But when I install them as the main hard drive, I get the question folder and no boot up. WHY? Any help would be appreciated in solving this issue. So I can read from the usb but not as the main unit. Do I need to change a setting or enable them to be read.
Just as info, I put in other hard drives in the pros and they work fine. But i want to install
these 320's as an upgrade.

After you installed one of the WD 320 GB hard drives in your MacBook Pro, did you then boot the MBP with its original install DVD, use Disk Utility to partition, format the drive, and then install OS X?

Installing the version of OS X from your operating Mac (whatever it is) and then inserting the hard drive into the MBP is not going to work.