WINDOWS 8.1 wont start

Problem started when the HP 500-424 PC running Windows 8.1 OS froze.
The only way to turn it off was to unplug the tower.
When plugged back in and turned on, multiple bootup attempts failed.
Attempted to put the computer in Safe Mode with Network via the bcdedit /set {default} safe boot network

I was able to run diagnostic tests, which passed:

Processor Check: Passed
Memory Quick Check: Passed
Hard Drive SMART Check: Passed
Hard Drive Short DST Check: Passed
Wireless Module Check: Passed
System Board Check: Passed
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Quick System Check: Passed

I attempted to save critical files via USB external drive, but got following message:
Recovery Manager could not back up your files. Possible causes:
(1) The removable disk drive doesn't have enough free space available.
(2) The system partition doesn't have enough free space available.
(3) A drive/disc compatibility issue.
(4) Destination device is not connected.
To fix this issue, free up some space on the removable disk drive and system partition, select another disk to back up your files, or ensure destination device is connected. If the problem persists, please contact HP support. Error code: 0xe0ef000e
Took out the hard drive Seagate HHD 2 Terabytes
Gave hard drive to friend who put into his tower, and it seems functional.
Friend was able to access the drive, but Desktop folders containing critical files couldn't be accessed. Anyone know why Desktop folders not displayed when looking at the hard drive contents while the hard drive was installed on my friend's computer system?
My friend saved hard drive contents onto his computer, which included Norton Virus Protection backups of the critical files, but when trying to open the critical files, they couldn't be opened, stating that the File names were too long??
Does anyone know how to overcome this " file names too long" obstacle when attempting to save and open Norton backups?

Reinstalled the Seagate HHD hard drive into my computer. All connections checked and secure.
Attempted the Recovery process, hoping to wipe the drive and bring the system back to factory presets.
Recovery attempt failed, with the following popup loop:
'Windows cannot complete the installation in safe mode. To continue installing windows, restart the computer.'
I was able to access the Command Prompt via Shift + F10
Unchecked the Safe Mode checkbox and saved.
Now every bootup attempts brings up a black screen without cursor, and nothing happening.
What to try next?

 

Yes I am interested in upgrading. How can I proceed?