Power ON and working maximum 5min and Power OFF instantly and within 3sec again Automatically power ON. This happend in BIOS / Windows / without HDD & without Battery also (with direct power adapter) I changed RAM, CPU, HDD, Tested without HDD, Re-install Thermal Paste, CPU Fan & Tested with Extra Cooling Methods. But no luck. I think this may be Motherboard Chip issue or a BIOS issue. I heat Northbridge with a Hot gun also, but no luck. Any expert please support or suggest. Thank you..