4-7 minutes into start OS unresponsive, pinwheel runs endlessly!

Early 2010 MBP 13” (A1278)

Problem: MBP is turned on without opening any programs but letting 4-7 minutes transpire, move the mouse via the track pad & “pinwheel” shows up and all programs stop responding. Can’t even use the normal shut down.

Happens whether you’re on battery power or a/c power supply.

Restart and retry, within the 4-7 minute programs stop responding and “pinwheel” comes up and nothing works.

I upgraded memory from 4GB to 8GB

Upgraded to a SSD hard drive, reformatted and Mac OS reinstalled

Changed Main Logic Board

Changed battery (original was 83 months old)

Reformatted and reinstalled several times with removal & full erasing & reformatting of the SSD drive

Thought it was the trackpad, started it without touching the track pad & keyboard & used an external mouse. I thought maybe solved… NOT!

Retried original memory and reformatting of the SSD drive (and original hard drive).

All the above failed... Same problem...

Any more suggestions?