Can you see the light blinking of the drive or everything remains calm and nothing can be heard from the fan or the hard drive? If so, I suggest you to take out the hard drive, if your lappy has no warranty and try to connect it to another computer through SATA-USB cable. If your hard drive spins up on a different computer and it is recognized there, but cannot power up on your laptop, then the problem is hiding probably in the power supply unit on your motherboard. While on another PC, I suggest you to make a backup of your files just in case.
Meanwhile your laptop is open, you could try resetting the BIOS through the CMOS battery. While you have the power cord and the laptop battery unplugged and if the laptop's warranty has expired, you can open the laptop and take out the CMOS battery. Leave it aside in order the electricity to discharge and then plug it back in. Try to start the laptop afterwards.
Have a nice weekend.