Specifically, new Del 3741with Win 10 unable to print to HP 5740

[staplers]

HP Officejet 5740 printer previously used with Windows 7 failed to print with new Dell 3741 computer with Windows 10 pre-installed  Reinstallation of 5740 software, and subsequent purging of all HP files relating to 5740, before reinstalling 5740 software again, had no affect.  Eventually discovered that "Spool folder" specified was c:\Users\<user name>, instead of C:\Windows\System32\Spool\Printers.  So the new computer with Windows 10 software pre-installed specified the incorrect spool folder.  The Spool folder name can be changed at Control panel\All Control Panel Items\Devices and Printers\<select any printer>\Print Server Properties\Advanced\Change Advanced Settings\Spool Server: enter the correct path to the print server: C:\Windows\System32\Spool\Printers.  The spool server can also be specified at  Registry KEY: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Printers

DefaultSpoolDirectory. Rename Value Data as : C:\Windows\System32\Spool\Printers.

This solution probably has no relation to a printer suddenly stopping printing with all things else being unchanged.  Conditions would need to involve some major software disruption like reinstalling Windows or purchasing a new computer with Windows pre-installed, such as the new Dell 3741 with Windows 10 preinstalled in this specific case.

Spent lots of time chasing other problems and solutions found on the internet (security permissions, Print Spooler Service settings, service dependencies, attached ports, compatibilities, ...) but this problem was due to an incorrect Print Spooler specification.