I suddenly booted my system into windows after ages and after restarting I was not able to see the grub loader option, so I was not able to select UBUNTU my favorite choice of operating system. It was directly login into windows os
But Thankfully I could resolve it using the following.
- Search for advanced start up option.
- Click on restart now in next menu.
- In the following menu click on trouble shoot.
- Click on advance option.
- Restart the computer.
- System will now boot into BIOS.
- Go to Boot order section using arrow keys
- Change the order by enter and drag
- press f10 to accept the changes.
- then escape.
This can also be done by pressing f10 while booting and directly go to BIOS. choose the boot order preference.