I've unchecked some wrong box in grub-customizer and now grub menu shows only windows. Can I boot Ubuntu using grub CLI and resolve this because I don't have Ubuntu live CD.I've even tried Super grub disk but it shows "BOOTMGR missing" error.Is there any other easier way to solve this problem which doesn't involve ubuntu live CD.
You can boot Ubuntu without a live CD, but it is a bit complicated. First you have to enter the grub command line: press c on the selection screen. you will probably have to load some modules:
then set the root partition, this is not your real root but where the kernel is installed:
auto completion should help here. Set the kernel:
again use tab for auto completion for the kernel. You will probably have to guess device (after root=) , it is probably something like /dev/sda1, /dev/sdb1. You will have to try till you find the rigth one.
then the initrd:
make sure to use the version number matches the kernels one. and finaly:
Your system should boot up now. You can try:
to fix your bootloader.