hsetir

I've been having issues with the cpu fan spinning up and down every 5 seconds. It's quite irritating. It started after the system crashed while playing game. Next reboot fan didn't move at all, and finally did after I opened the back panel and reconnected the fan. Now the fan is fluctuating continuously, even when inside the bios. So, might not be a driver issue. There aren't any fan or temperature controls inside bios, but the windows shows all temperature well below 50 C. Any suggestions?