farnell121 :
Try pulling the HDD out, the RAM, and leave the battery out. Make sure that the Power Supply is for that model laptop or if it is aftermarket that it has enough Wattage to power the laptop while the battery is removed. If the battery has gone bad this can cause boot issues sometimes. If there is like a watch battery under one of the panels in the laptop try removing that as well.
you can try to boot without the RAM and Hard Drive and see if you at least get any error beeps. Also, let me know what the lights on the laptop look like, plugged in with and without the battery.
There are 3 LEDs and one is charging, second is power and third is i dont know.
When i tried to turn it on, the second led lights up for 2-3 secs as always, and ive done what you said. The first led lights up too.
If its without the battery its the same thing.