Bad internal power supply. fan bearing squealing, grinding and resetting PSU. If seller actually tested unit they would have noticed it. Had to buy a second hand HP 200w replacement power supply on ebay for $36.00. Also. Benchmark results showed temperature throttling on the cpu. Thermal paste was dry and brittle. These units are not renewed. I will be more careful in the future and stick with my regular sellers on amazon. You have been warned.