have you done any modifications in bios/uefi settings. if not, it is usually caused by a malware. in that case, see solution here http://www.tomshardware.com/answers/id-3230874/laptop-turns-windows-log-displayed.html
boot into safe mode with networking. install an antimalware. my preferences are comodo internet security or malwarebytes anti malware. update to max and run a full scan. after cleaning the malwares, install toniarts easycleaner and run registry cleaner.