I have a Dell Inspiron with Windows 10 that was insanely and painstakingly slow after upgrading from Windows 7. It has 8 GB RAM and I tried numerous solutions to speed it up without luck. I then installed Ubuntu and Grub handled my boot options. I then had issues and did not uninstall Ubuntu properly. Long story short, my boot screen is somewhat buggy now.
I have a Legacy Mode that shows the options: Network, Hard Drive I have a UEFI mode that shows HDD1 - ubuntu, HDD2 - Windows 10, HDD3 - Ubuntu. The 1st and 3rd options don't work. They result in the Grub shell loading and ending in an error.
I have tried repairing it using a live usb but that didnt work. I am not sure about the next set of steps to take at this point.
I can post detailed screenshots if that would help.
Edit1- I have reinstalled Ubuntu and I can get to it using the Hard Drive mode from the Legacy boot mode.