Hp Pavillion dv6000 will not turn when hit theon

A lot of times these laptops are in a sleep mode (after a certain period of time which is decided by the windows or the user, the computers turn of the screen). I would start by pressing on the power button for a long time (about 1-2 minutes), then try all the basic stuff:
1. check the laptop's cable, if it looks okay or not, maybe there's a problem charging the battery.
2. try replacing the cable and the battery.
3. try removing the battery for about 24 hours.

update me if you have any developments