I've got an ASUS K70AB Windows 7 laptop. It was in storage for over a year because a couple keys broke off and the power charger was lost.
I installed a new keyboard (very simple to pop out the old one and put in the new, no deep-diving nut & bolt extraction required) . . . and got a new power charger.
The first couple boots seemed fine as I was doing all the Windows updates. Then later that day after it went into hibernation mode, I pushed the power button, but the screen stayed black.
I've since rebooted it about 70 times, and roughly 3 of those times I actually got a display.
Within 2 seconds of pushing the power button I can tell if it will work, because the Caps Lock, Num Lock and Scroll Lock buttons blink.
If those 3 buttons didnt blink right away, even giving it 10 minutes, nothing happens.
I've tried swapping the 2 RAM chips around and 1 at a time... no difference.
I've tried hooking my laptop up to a working monitor... monitor stays black just like the laptop screen.
I dont think its booting to windows, because if it did, the caps lock key would turn the caps lock light on. The fan does not turn on either.