I think this from AZorin How to fix the boot menu if it disappears
is the same but I didn't try it yet cause I have to restart and the the Grub command thing again to be able to access the BIOS and be able to boot from a usb stick (if it works at all 
I wrote the Zorin Iso on to the stick so I guess I will try this now...
Be right back 
hopefully 