Try a full power refresh and check if that resolves the problem. It may be that a corrupted BIOS is preventing a normal start.
- Turn off the laptop if it is on and disconnect the charger from the laptop (if connected).
- Remove the main battery from the laptop.
- Press and hold the laptop's Power On button for a full 30 seconds and then release it.
- Reinsert the main battery, reconnect the charger and check if it turns on OK.
If it turns on (or even if it doesn't) but then the same thing happens again some time later (days, weeks even) it may be that the RTC battery (Real Time Clock aka CMOS battery) on the motherboard needs to be replaced. This battery maintains the BIOS settings when the laptop is turned off and when its voltage get too low (usually <2.5V DC) the BIOS can become corrupted.
Unfortunately this battery is mounted on the underside of the motherboard, so the laptop would have to be nearly completely disassembled to get to it.
Here's an image taken from this dis-assembly video that shows the RTC battery on the board.
(click on image to enlarge).
The model number of the battery is stamped on the battery itself, but usually it is a CR2032 which is available most everywhere e.g. supermarkets.
You may find that after the RTC battery is removed/replaced that when the laptop is turned on, there's a message saying that the date and time is incorrect. This is normal as the BIOS has been reset back to factory default. Once the D&T have been corrected the message won't appear the next time the laptop is turned on.