Dear Tech Support, Before you ask, yes, I have tried turning it off and on again! I decided I would back up my data and go for a format, and create a dual boot with Ubuntu and Win7 so I could check out Linux. When my first batch of 'copying' and 'pasting' to the internal second drive had finished I noticed that my second drive had disappeared ... vanished ... kaput! So I rebooted and it came back. Did some more copying - but that never finished, the copying window went 'static' for an age, and I had to reboot the PC again. Reboots and copying and pasting, I am now backed-up. My worry is that I do not know if it is the drive, PSU, mobo or just win7 corrupted. So what do I do now? I'm worried I will go to all that effort to reinstall on another drive, only to find out it is not the drive and it is something else. Kind regards, confused!
When drives are doing strange stuf, i first replace the SATA cable, then the SATA power cable, then i run the manufacturer diagnostic tool. If the tool reports an error, i am sending the drive for RMA, if not then it's time to test the drive (and after that the various parts) in different PC and locate the failing part.
In my experience unless you have plugged and unplugged or moved the drive when it starts disappearing from the computer the Drive is not far from buying the farm. I would run a test on the drive to see if there are any issues. I.E. the utility from the manufacturer. That is just my personal experience especially if it is data you value. But the above suggestions are good also if you have moved anything.