My inclination would be possible harddisk/memory problem aswell. Possible corrupt file, but if it happens every few hours I'd lean towards hardware. The CPU overheating is also a good possibilitity. I've certainly seen a fair few where the cooling fins become clogged with a thick layer of dust effectively stopping airflow (and cooling).

See how you go with the options you found on google. If you're still encountering problems your next step is to take it to a service centre. Preferably one that has a laptop dept or specialises in laptops. [plug] [/plug]