Need help troubleshooting a dead hard drive!

Hi everyone,
I am new to this area and have been reading posts from others for the last two weeks. I have two Western Digital hard drives and one of them just died lately. Computer BIOS recognize it as 0.0 GB. no other information is shown in BIOS for the dead hard drive. The hard drive spins for a few seconds every time I power on the computer.  I have a second hard drive with the same brand and model:

Bad drive, patient:
model: Wd15eads-11p8b1
Date: 27 Jan 2010
DCX: 9019P2S80
Made in Malaysia
PCB: 2060-701640-002 REV A

Good drive, donor:
model: Wd15eads-11p8b2
Date: 11 Feb 2010
DCX: 5021P2T84
Made in Malaysia
PCB: 2060-701640-007 REV A

What can I do with the donor hard drive to possible fixing the bad hard drive?

0- What is most likely the problem with the hard drive? 

1- how do I test for the components on PCB board for failed TVS, which one should I test?

2- Is the donor PCB board compatible with the patient board for the PCB board swap include the U12 swap?  They have the last number different…

3- Is the donor drive compatible enough for the head swap?

Thanks everyone in advance!

Please help!  any one???