Inspiron 3470, Windows 10 boot failure

I got an Inspiron 3470 just before Christmas. Worked great for 2 weeks then refused to boot after POST. Thought it a one off and restored Windows 10 from scratch and loaded all my programs again. Now it has happend again. Following POST just a black screen. Been through Support Assist which reported the failure as OS_BOOT_FAILURE. No problems found in further checks. Went through DISKPART and bootrec fixes. But still will not boot. I can reinstall Windows again and I am sure it will work. But I think it will just fail again after several weeks. Updated BIOS to 2.14.0.

Any suggestions?