Repair something inside or taking out the hard disk should always be possible. Find the repair manual and see how. Since you didn't tell anything about maker and model nobody here can tell anything more detailed, I'm afraid.
A new motherboard most often is too expensive to consider a viable solution.
So i was playin video games on my laptop for a few hours and then it shut down. Apparently my cooling pad wasnt working and the bottom was really hot. I think its a fried mother board but the bottom is fixed/ unremovable. I cant check the parts nor replace them. Is there anything i can do to fix my computer? Or at least recover files?