My Acer drops power intermittently, and will not poweron afterwards.
The only way to switch it on again is to remove the battery and the charger for some time.
It may stay on for several minutes or even more than an hour and work fine.
The problem occurs running on the battery or the charger.
Just reconnecting the charger and not switching on the laptop will result in the same fault condition.
+3v and +5v are missing in this condition.
Checking arround the Intersil ISL6237 chip I discoverd a very sensitive point which cause about the same symptom....