Power flashes on for a second and then turns off completely

I suggest that you remove the battery and use the charger only in turning on your computer. If it turns on just fine without the battery then you would need to replace the battery. If it doesn't then it's either the motherboard or the charger which has a problem.
David

If it EVER works, then the problem is not a failed part, but a weak part. The most likely component type to give you such problems are capacitors. But very few repair techs know how to find such problems, and even fewer have the equipment needed to find the bad one(s) in-circuit. The failure mode is high ESR (ESR means Equivalent Series Resistance). The lower the ESR, the better. Capacitors with high ESR cannot stabilize circuits which demand high pulse currents, such as in switch mode power supplies.

I doubt there is battery problem, have you tried switching on laptop without battery and connecting through the laptop charger? most probable your battery is not taking the charge. so suggest you to disconnect the battery and try using laptop with charger then you'll find the problem.

MOTHER BOARD PROLBME

Are you sure you are turning it off completely. Sounds like you have it sleeping or hibernating. Press and hold the power button for 15 seconds or so, it should power off completely.

check your video cable ends for bent pins or debris, then make certain that they are plugged in straight and tight.

Hi.

Take out the AC power jack and then remove the laptop battery. Plug AC power back in and see if the laptop will turn on. If it turns on let it boot the operating system and then shut down as normal, remove the power cord and reinsert the battery and again see if it will switch on. If it does then there has been a glitch with the battery. If it doesn't then there is a problem with the battery.

If the laptop won't switch on either with or without the battery then there is a possibility that the motherboard has developed a problem.


Good luck.

Laptops are so integrated that usually a system failure that involves power issues such as in your case where you cant get it turn on with anything on the screen mean the mainboard (motherboard) is damaged. This usually leads to buying a new laptop or paying for the board to be replaced which usually costs as much as the laptop.