A while ago I installed Ubuntu on a separate drive. I've been booting it from this separate drive ever since. Now I'd like to install Ubuntu on a dedicated partition of my laptop main drive. I've extracted the relevant iso content into my usb drive ready to re-install Ubuntu but unfortunately the installation does't boot up. I thought it was because of the grub terminal I get to see every time I turn on my laptop without inserting the separate drive I've mentioned before, so I researched how to get rid of it and I found and followed a guide that will take you to the win 10 safe mode terminal to run the bootrec/ bootsectcommands.
I've run both of the commands but yet my laptop still boots with the grub terminal screen and the usb drive still doesn't load the Ubuntu installation.
My goal is to install Ubuntu on my main drive and will probably end up re-installing the grub; what can I do to achieve my goal (whether it will take to remove the current grub effectively or not)?
Please help it's urgent.