Answer to "Shutdown while boot up, same problem within cmos setup. help."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..