Shortly (a few days) after reinstalling the system, my Dell Inspiron N5050 can't boot. It goes through the Dell startup screen, but doesn't start Windows. In BIOS my hard drive is listed (both by name and capacity), but while running the diagnostic test, the output is:
Error Code 2000-0142
Msg: Hard Drive 0 - S/N S2W8Q2JH, self test unsuccessful. Status = 7
Is the HDD dead? Any hints would be appreciated.
Yes the hard drive has failed. The only thing you can check, and this is highly unlikely, is if the SATA cable is loose on the hard drive. Otherwise you will have to replace the hard drive.
Since you have to replace the hard drive anyway, this might not be a bad time to upgrade to an SSD. The performance would be much better and it gives you a chance to clean install Windows.
If you want to recover the OS as it was shipped from the factory then the link below will help.
An ssd would be a waste of money on this old model that cannot run windows 10. Use as is with a new hard drive until you can replace the computer or save the cost of a new hard drive and take this opportunity to replace it now.