I am very pleased to report that I believe this issue has been overcome. I jumped thru all possible hoops short of upgrading to Windows 10, which I was preppared to do.
The good folks at Focusrite tech support after severl very positive communications, after perusing my dump repports, diagnosed the issue as driver
verifier was running and this interferes with the Foususrite drivers.
My DAC has been running for over 4 hours now with no issues (BSOD).
Thanks everyone.
Whit