help, yoga won't boot up in safe mode, can't restore

[syrahnose]

How can I boot into safe mode? F8 doesn't seem to work. How can I get to safe mode and do a system restart?

Problem is everything was working fine last night, then it wouldn't turn on this morning. electricity getting in, but dark screen. An auto win 8 update happened before this happened, but completed with full battery and power cord on.

My daughters Toshiba had similar problem on same win update and wouldn't boot up either. I fiddled with it and took out battery and put back on power cord and it healed itself, booting up with no problem.

I'm wondering if TPY had same issue with upgrade, but no way to take battery out to circumvent issue.

[syrahnose]

fixed it. I held down the start button for a minute and somehow it seemed to break the cycle. Then pushed again and it booted up.

[RealBlackStuff]

Holding down the power button for ~20 seconds, with battery and AC removed, will cause a hard reset.
Basically all capacitors on the laptop's motherboard are drained that way.
And many laptops are brought back to life that way.