This is NOT an installation problem question. I've had both op sys working fine side-by-side for a couple of weeks now. I'm using Ubunutu 12.04 64-bit.
This morning when I tried to switch from Win8 to Ubuntu, it just rebooted into Win8. No grub screen whatsoever. This is the 3rd machine I've had dual-booting & have never seen this, but then Win8 is a 1st for me & has thrown some pretty awesome blocks in the path to get to here. Atrocious op sys…
I'm assuming the ASUS updater did this yesterday. (ASUS R503U)
So, do I just put the Ubuntu disk in & reinstall grub?
Best Answer
No you need not to install Ubuntu again
Here is your solution:
I prefer you to use Ubuntu Grub Menu, that is let Ubuntu to allow you to chose which OS you want to boot (Windows or Ubuntu).
Here are the steps that would help you..
Boot from your Ubuntu LiveCD/DVD or Ubuntu bootable USB and select 'Try Ubuntu' (not 'Install Ubuntu'). When Ubuntu starts open terminal (CTRL+ALT+T) and execute following commands:
Installing boot-repair ( a good s/w to fix grub ):
When started select Option 'Recommended Repair' from out of two options:
'Recommended Repair' & 'Advanced Options'.
Follow very easy onscreen instruction, it will build/fix your grub menu..
Restarting your system may list all the Operating Systems installed in your HDD. Be sure that you have properly shut down Windows 8, before starting these steps..
You can get more help on - Using Boot-Repair