For nearly a year after Windows 10 came out, a bunch of pre-Windows10 applications were working.
For example, Paintshop Pro 8.1 OEM since 2003 was working, but stopped.
Low and behold, the final issue was resolved by the following:
Set the permissions on C:\WINDOWS\TEMP to EVERYONE and./or AUTHENTICATED USERS = FULL CONTROL
that I have been using CS4 Photoshop for the past year, I am quite
pleased with having to leave Paintshop Pro 8.1 OEM in the past.
it today made me smile and return to enjoying it since I have tons of
files with .pspimage extension that I can now open again without having
to revert to a Windows 7 machine.
more to come...