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My laptop originally came with Windows 8, a while back I tried to install Ubuntu, but it didn't work so I just deleted everything. Today I did a factory reset on my laptop because I am going to sell it, but when I boot it boots to a black screen that says "GNU GRUB version 1.99-21ubuntu3.1" followed by a bunch of text. To access Windows 8 I have to hold down f11 on boot where I get the option for windows boot manager. I want to make Windows 8 the default, how to I get rid of this "ghost" ubuntu?