when i start my pc, it works for half hour to 1 hr. fine, then suddenly turn off, If i restart the pc immediately, noise come and a message on screen displays is CPU shut down due to overheating, press any key continue, this is when cabinet is closed, when cabinet is open then PC shut down time is more than one and half hour, pl. suggest what to do to solve this problem.
Sounds like you should clean the case intake fans, clean dust out of the case interior, and verify that the fan and heatsink on the CPU are firmly attached to the board. Clean dust off the CPU fan. You may need to clean and re-set the fan and heatsink on the CPU, by removing it, cleaning the cpu and the base of the heatsink with alcoholwipes, apply new thermal compound (like Arctic Silver 5), and re-install the heatsink and fan.