It could be a lot (really, a lot) of things that can make your laptop do that issue. So, let´s start with the simpliest procedure:
1- Try taking off the battery and the plug in the power cord and try to power-up your device, if it works, you´ll need to replace your battery, but you can used without it anyways.
If the problem persist,
2- You´ll need to take off the RAM memories and try to clean it up( you can do this operation with an eraser, cleanning the golden contacts; make sure you don´t left behind any remains of the eraser in the memory). If you have more than one memory try each independently.
If the problem persist,
3- You need to fully dissasembly your laptop and take a close look of the motherboard, maybe (if dirt on it) try to clean it up with a brush and some isopropyl alcohol.
If the problem persist, leave a comment so we could continue trying to help you.
Good Luck!!