I recently finished building my new computer however my case fan doesn't turn on unless I go into BIOS and save my changes and exit (even if I don't actually make any changes). My case fan is an Arctic Cooling 120mm fan. I don't know if this would make a difference but my case fan is powered through the CPU fan power and the CPU fan connects to my case fan wires to get power because I only have one 4-pin power socket.