It's always annoying when you put away a usable laptop and then find a while later that it won't boot up or show signs of life.
Here's some first aid suggestions for you:
1 Disconnect your power supply/mains charger from the laptop and check the output voltage ( a simple voltmeter preferable digital, will do the job) it should show an output of 19v If the output shown is within one half a volt of 19v then it's likely the power supply mains charger is OK, its not a definitive test but usefully indicative.
2 If the power supply is showing 19v then check the power gauge on the battery (you need to invert the laptop unlock the battery compartment using the sliders and check the gauge...... If you have fitted a non standard battery rather than an OEM one then it may be that the gauge is not present...
3 Remove the battery and place it somewhere safe, and unplug the Power Supply/mains charger from the electrical outlet socket (wall socket) and also uplug the output wire from the power supply/mains charger to the laptop. Check carefully that there is no disc in the DVD/CD drive (you can open the drive tray usually by using an opened paper clip in the small hole set into the tray.) Check also that there is no card of any sort in the card reader slot. Now discharge the capacitors by pressing and holding down the "power on" button for 20 seconds, then releasing it, waiting for 20 seconds and then pressing and holding in on again for a further 20 seconds Please do not skimp on the timings, count or use a stopwatch to ensure that timings are accurate, This will help to ensure that all residual charge that may remain in the capacitors is fully discharged.
4 With the battery still removed and stored safely, reconnect the power supply/mainscharger to the laptop and then energise the power supply by plugging it into the wall socket. Switch on the wall socket if it has a switch (you can test the wall socket by temporarily plugging in a lamp or other device.)
5 With the battery disconnected, but the power supply/mains charger plugged into a working wall socket, attempt to start the laptop in the usual way (press and hold in the " power on" button for one second only.)
If the computer shows signs of life then rejoice! but if it doesn't report back here with your findings., and one of us will advise the next steps.