Lenovo T400 Fail to boot up

My lenovo Thinkpad T400 it's not booting up , when i power on it shows only the first page you know " Think pad to interrupt normal start up ... " and than it stay like this ...
I've tried to press the power button 11 times and then keep it for 30 sec but it didn't work... harddrive is alright , ram checked I suspect that this is a motherboard issue or maybe a AC power problem ( but since laptop lights are turning on also laptop itself turns on ) ... can anyone help me