i had installed ubuntu 15.0.4 on an external hard drive. My pc booted up windows automatically although I could boot into ubuntu by going in the boot device menu and selecting the Ubuntu("somecode") entry listed along with OS boot manager from start up.
Now I deleted ubuntu from my external hard drive but I can still see the Ubuntu("somecode") entry listed in the boot device menu although it leads to grub saying ubuntu isn't installed.
How can i remove this entry and thus any instance of ubuntu from my pc?