startup disk no longer available
My 2015 Macbook Pro all of a sudden stopped turning on. I contacted Apple Support and they told me what to do... from there I still had problems with my computer starting up and I restarted it many times. Looked up youtube videos on how to reboot and did lots of "Command" "R" and "Shift" rebooting. Sometimes worked... but once my I tried to turn my computer on the next time a folder with a question mark kept flashing... Ive been trying to restore my disk through "Disk Utility" but there is no startup disk to be found. I am stuck, please help!
MacBook Pro 13", macOS 10.13