As I said in the title my Asus GL502 is stuck in a boot loop. But after disabling fast boot and secure boot and enabling CSM boot on startup it said that it cannot find a boot device. After checking on the net I found out that it means my system cannot connect to my SATA 1000GB storage (which is strange because the laptop worked fine until now).After another search on the net I found out a solution to the booting problem - pressing ctrl + alt + delete during the CSM boot.But the fact that my system couldn't detect my storage device bother me, So i'll be more then happy if someone could explain to me why my system suddenly cannot connect to my storage system and why pressing ctrl + alt + delete fixed the problem.
To be honest, it sounds like what you did reversed whatever changes were made. If that is the case, then that would explain the fix. It is hard to give an answer when we don't know exactly what was done and why, steps taken, what the computer had on it prior, etc. To many variables.
Were it me, I would just be happy it was working again and save the questions for a later date.