OK this is interesting. As you may know for several weeks the Intel GMA (Graphics Accelerater) was keeping Windows 10 from installing on Clover Trail based tabs (W3 and W510). About a week ago "something" happened and it began installing but only if every important and optional Windows update had been applied.
Shortly afterwards we noticed that if you opened Device Manager>Sytem Devices every Intel (R) Dynamic Platform and Thermal Framework drive was flagged with a yellow "i" and had not loaded properly. Also all except one services were stopped.
Apparently what had happened was that "something" in the upgrade process also upgraded the DPTF drivers to version 7.1.0.20. This version does not seem to work.
Now examination of the latest Acer driver set (3.02 for the W510 and 2.01 for the W3) both contain the same set of DPTF drivers: 6.2.9200.30457.
Replacing the drivers with the ones from ACER cleared all of the yeelow "i"s and it boots clear now.
Moral: if you upgrade a W3 or W510 to Windows 10 you may need to roll back the DPTF drivers to the ones released by ACER. (from Device Manager, open each DPTF entry and select Properties>Driver>Update Driver>Browse my computer...>Let me pick... and select the 6.2.9200.30457 then reboot)