We are awaiting the model number of your laptop. Once we have this we can accurately tell you how to replace the power button, or if it is possible.
OK dragon: Now with this info we can proceed.
Your laptop has a power button on a separate little pc board. Can you believe it is attached to the hinge.
It is replaceable along with the hinges . There are a few on e-bay for around $30 some from Great Britton. Shipping average is $15 and one dude from the USA to Canada wants $125. Good luck.
The power button like I said is under the lid attached to the right hinge. It has a mechanical actuator that lives just under the lid that presses on the power button. If the hinge is damaged it may be pulling the screws out of the case. This in turn has ruined the micro switch jut below the lid under the actuator for the button. I would say the only way to get it to run is remove the back of the laptop and take a look at the damage. With the back off you can see the hinges, plus start button. With out taking any thing else apart. Assess the damage then before purchasing the parts.
To replace the hinges you have to take it totally apart but can leave the mother board in, cooling , memory, hard drive. But you have to remove the LCD screen as the hinge runs up the top lid under the screen.
Do not be shy find a Philips jewelers screw driver. Do not loose the screws, the back just pries off with a little coaxing, flat blade knife. Easy though do not pry all in one place work around the lid edge.
Have an adventure with it. Good luck.