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I was trying to install Ubuntu (the installation went well) while already having installed windows 8. After installation I wanted to change the boot option back to hard drive but this option wasnt there, only CD/DVD option. Now I am stucked in BIOS not knowing how to boot from hard drive. I have ASUS N56V laptop.
Could try switching to/from legacy mode or to/from uefi mode depending on what it currently is. Otherwise, reset BIOS to default settings and see if that helps. You could also try reseating the hard drive, but that seems unlikely to help – Blaine – 2016-09-27T03:34:16.617
1It seems that this BIOS have a "secure boot" option which can limit boot options. How is the drive partitioned - MBR or GPT? Is UEFI enabled? There could be also a backward compatibility option called "CSM". – pabouk – 2013-12-09T12:17:43.063