Yosemite-fail to boot new HD!!

[yabbyman]

Hi Guys
at an absolute wits end with my iMac running OSX Yosemite....
Initial problem was "supposedly a dudded HD" (question mark et al.
Apple replaced the HD and claimed that they could not recover any data. (thank dog for time machine)
Anyway.... got the iMac back with new 1TB HD, booted up and it immediately recognised that it required all the data back and it appeared that it was doing a great job. Then post this a restart and it failed to properly boot (recognised HD and general machinations though just the gray screen with the revolving single color wheel of death)
Tried rebooting to no avail.
Disconnected all ext devices, ethernet and shut down wifi router - no joy
tried rebooting and did:
SMC
NVRAM (never even got that far)
Recovery mode
Safe and Verbose boots - no joy either
(hanging before it even gets that far.
Did reboot in recovery mode - zip
Just doesnt get that far

Absolutely nothing!!!
My gut feel is that there was probably nothing wrong with the HD in the first place and that no effort was undertaken to see whether a) the HD was OK and; b) no effort was done to "retrieve any data.
Anyone with any suggestions or experience?
Look forward to any constructive opinions
andrew

 

[keysofanxiety]

Could potentially be RAM or MLB. You mentioned you tried recovery mode (Cmd+R?). Does that boot into that? Did you have an opportunity to verify the disk in Disk Utility or try a clean install (wipe Macintosh HD/Reinstall OS X)?

At any rate if it's still under warranty I'd definitely take it back to an Apple Store.

 

[pedro_martins]

If I was you, I would go to recovery mode, delete the HD and do a fresh install. Then, I would think about the time machine data.

Actually, use Disk Utility to search for errors/fixe permissions and so on on your drive after you erase it.

 

[Fishrrman]

OP:

I know the following advice can't help you -now-, but it could be a big help in the future.

If you had kept a BOOTABLE CLONED BACKUP created with either CarbonCopyCloner or SuperDuper, it would be a trivial matter to get the iMac booted up, even after having problems with the newly-replaced drive.

Just connect your bootable backup and go.

From that point, you could "work on things" to get the internal drive healthy again.