I formatted my dad's PC because there was a freezing problem on it. Before the format, my Dad's PC used to turn off ever 5-6 hours by it self. After the format it turned off ever 2-3 hours. So I opened it up and cleaned out the dust that has been accumulating there for ~7 years. I reapplied the thermal paste and readjusted the heatsink. The Computer now freezes ever ~30 seconds, when I turn on the PC and check the CPU temperature from the systems menu I get ~80-95 degrees Celsius. What could the problem be? The CPU fan is turning, the heatsink is new, I used new thermal paste and applied a (decent but not too much) amount... Can anyone help? Thanks
Open up the computer and check for any bulging or busted capacitors on the motherboard. That can cause system instability and rebooting.