I have dual boot of windows and lubuntu on my laptop and all is working fine except for sometimes, the shutdown wont work. Last night, shutdown wont work for my lubuntu again so i just kept it there, then when i tried to turn it on and it was just full black screen, then forced to shut it down by pressing and holding the start button, then start again and, the grub doesn't show up anymore. Then i checked that secured boot was turned on again. So i turned it off, but as a surprise, the grub still wont show up. I have a lot of files there that i really need. Is there any way i could add grub menu again using windows only?