Sounds like the laptop is not passing POST (Power On Self test) on startup. Try a full power refresh in case it is a corrupted BIOS and check if that resolves the problem.
Here’s the procedure:
a). Disconnect the charger from the laptop if connected.
b). Remove the main battery from the laptop.
c). Remove the RTC coin cell battery from the motherboard.
Here’s the hardware maintenance manual for the laptop. Go to the bottom of p.60 and p.69 to view the necessary pre-requisite steps and then the procedure to remove the battery pack and the RTC coin cell battery respectively.
When the coin cell battery is removed measure its voltage. If it is <2.6V DC replace it. The part number is 02K7078. If you search online using the part number only, you will find suppliers of the part.
d). Press and hold the laptop's Power on button for a full 30 seconds and then release it.
e.) Reconnect the RTC coin cell battery (or its replacement).
f). Re-assemble the laptop and reinsert the battery pack.
f.) When the laptop is completely re-assembled, connect the charger and try to turn on the laptop.
If it starts OK there may be a message about the date and time being incorrect. This is normal as the BIOS has been completely reset back to its default settings. Once the date and time have been adjusted the message won’t appear the next time that the laptop is started.
If you had previously changed any user defined settings in BIOS to suit whatever specific hardware configuration that you had for the laptop, then these will have to be set again.