Stuck on boot menu

Hi
My Lenovo G580 laptop won't start up. When I turn it on using the power button it goes straight to boot menu/app menu. There are various options there to choose from, but whichever one I choose, it keeps going back to boot menu. I've tried using the novo button, but it still doesn't work. Whatever I choose from the novo button screen, except "BIOS setup", keeps taking me back to the boot menu. My laptop won't start up, and it's really frustrating! Please help?!

Thanks