Re Error 8506.421 still a problem on the Tohiba not the HP Envy!

Re Error 8506.421:  I have downloaded and run Norton Removal Tool, followed the on-screen instructions, restarted the Toshiba running Windows 7 and re-installed Norton Security.  I have also downloaded Norton Power Eraser and followed all the prompts including Rootkit scan.  I restarted the computer, and followed the on-screen instructions for Norton Power Eraser.  However I still get the same error message re Error 8506.421 that Norton cannot fix it.

Should I run Norton Removal Tool again and Norton Power Eraser again or is there another solution I should be considering?