laptop won't turn on when on battery power (battery is fine)

[LTadic]

I have an HP Envy that's 18 months old (purchased November 2013). After working fine all this time, now the laptop won't turn on if it's running on battery only. The battery itself is fine; if I unplug the adapter when the laptop is already on through AC power, it shows the battery has 97% remaining. Is there a setting that I'm missing? I've used it on battery power before all this time without a problem.

 

[C12Friedman]

Welcome to Tom's Hardware Forums,
I'll suggest trying a reset.
Unplug adapter from laptop, remove battery then press and hold power button for ~30 seconds. Put battery back in, try starting on battery then.