my two Seagate Barracuda 400gb drives that date back to 2008, and i'm not trying to bring on a failure!, 
but these two drives are going strong, with naught but a couple of defrags in all this time...
 
2016-2008 = 8 years old.
 
 

FYI recent reliability statistics:
https://www.backblaze.com/blog/hard-drive-reliability-stats-Q1-2016/
 

so what i'm reading, suggests i should just keep my old hard drives!!!
 
if they haven't failed yet.........

So... my main HDD (Samsung Spinpoint 1TB ) just crashed ! I'm now re-installing Windows 7 (done, updating other drivers now) onto one of my older Band In A Box portable HDD (it's a Toshiba notebook HDD inside).
 
How it crashed ? - I was copying some MP4s transferred from my handphone into a compressed ZIP folder. Then I was browsing a PDF file in the handphone folder ..and the PC hung and did not respond.. I do the next logical thing.. hard powering the PC off (long press on the ON button).. and upon booting up - there is no longer any boot disk.
 
Edit : Task Manager can't be started (Ctrl+Alt+Del).. so hard powering off is the only option.
 
Checking the bios SATA device only shows the other drives (Backup and Samples).. removing the main drive into another PC also can't be detected (I hear the spin sound, but not as loud, and no disk head movement).
 
So.. I'm still considered lucky to have just moved some recent project into the Sample drive, and I was working on my latest project last night on the Sample drive... I'm still thinking what's important in the main HDD.. Quite a few folder in the desktop did not make it to the Sample drive.
 
Beside all the MP4s / pics I've just moved over to the desktop prior to the crash (files from the handphone was deleted automatically after moving ) - but I guess I might still be able to recover missing files from the phone SD card.
 
So.. my advise.. any drive that is 4 years old should be replaced, and move it to temp / unimportant storage.

I have had my primary drive (SSD) go "offline" to the BIOS a handful of times, and never did find the reason why. In a couple situations, a cold boot fixed the issue, but when that did not work, the following did (also baffling):
 
I inserted the newest Windows Repair Disk (created by Win7). Went through the bootup, selected "Repair" (which does a search and says "cannot repair since the installed version is newer" or some such). Exited, shut down, and rebooted, and the SSD came back online.
 
Not sure if this is an option to try since it seems you already headed down the re-installation path. In the event of a true failure on a HDD one of two things would occur in most situations... 1) you will hear the heads "seeking" but get no response (failure of the head on the Master Boot partition) or 2) nothing at all (the circuit card attached to the drive failed or something in the connections went belly-up). The "going offline to BIOS" is not unheard of, and the best I can tell in my situation was a firmware (driver) issue that could only be updated at a very specific step in the Win7 installation process (this is specific to my SSD, since its own updater cannot recognize the SSD as an attached device after a certain point in the Win7 update cycle).

ston
My chart:
 
1990: omfgwtf HOW MUCH?! I could buy Switzerland for that. £1M for 1TB
2016: LOL!1 cheaper than peanuts, roughly 20,000 times cheaper
 
20 thousand.  Times.  Cheaper.  Tell me something else that was available in 1990 that's now 20K times cheaper :-)

4 Megabytes of RAM in 1992 £104. Or £26 a Megabyte.
16 Gigabytes DDR4 RAM (= 16,777,216 Megabytes) in 2016 £66.42. Or £0.000004 a Megabyte (approx).

My quick (and probably wrong) arithmetic reckons that's a factor of, what, 6,500,000? And that's without taking 24 years of inflation into account, which would make the price per MB even less now compared to 1992.

And people complain about the price of RAM... :-)

mettelus
I inserted the newest Windows Repair Disk (created by Win7). Went through the bootup, selected "Repair" (which does a search and says "cannot repair since the installed version is newer" or some such). Exited, shut down, and rebooted, and the SSD came back online.

 
Thanks for the suggestion, I shall try this option later as I may have created a repair disk some time back.
 
I needed a working Win 7 to recover the hand phone SD card deleted files. Using Photorec "dos interface" freeware, I was able to recover almost all the files.
 
Just last week I was helping a friend, where a similar message appears, the boot disk (HDD) was not found. But after a fresh reboot, it works. Perhaps sign of failure coming.
 
Meanwhile, I'm thinking of buying a similar used / refurbished HDD to swap the PCB board and see. It's crazy that that I've discovered older model HDD sold brand new is much more expensive. Even more expensive than current larger size HDD.

Update : I've ordered a refurbished same model HDD. Hoping a PCB board swap will enable some recovery (the PCB board swap itself is quite easy - credit to many youtube videos).
 
And this is when I discovered.. The Samsung Spin Point F3 I've been thinking I had, is actually an older F1 version. F3 was the recommended drive to get from this forum and I specifically told my local IT store the model. Somehow, HDD bare unit in anti static bag don't usually have the word F3 or F1 printed on it and I trusted the store for giving me the right model.. Not sure if the F3 would have lasted longer. Maybe it would as PCB board overheating is listed as a common problem with the Samsung Spin Point drives.

Be sure to ground yourself when working with electronics just in case.

Newegg had a 5TB WD Black for $189 today.