If the warranty of your laptop has expired I suggest you to take out the hard drive 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. You could bring your laptop to a technician to make a test of the power connector and/or the power jack center because they might have got damaged.
Also, there's another thing you could try and that is the CMOS battery replacement. Have you done it already? If not, may be the time for that has come. Take the power cord out of the laptop and ope na the lid. Localize the CMOS battery which looks like a battery for a watch. Take it out for about 10 mins and plug it back in, if you don't have a new one. Then, try to boot you lappy once again.
Hope I gave you an idea.