My laptop won't turn on....

hi everyone i got a problem on my laptop.. it goes like this i press the power button and it wont turn on i tried what they've said remove the battery press the power button for 58 seconds return the battery nothing happens... but when i plug the ac source it turns on,, after it turns on i remove the ac source and it still working.. what might be the problem here? another thing is that it won't shut down i also tried all suggested in the net that i would uncheck the restart automatically ... but still after i shut it down it restarts instead i hold the power button to force shutdown but nothing happens it still restarts....
please help me guyz my dad would scold me if he learned about this ... i would wait for your reply