I have two partitions on a single hard drive. One with Ubuntu and one with Windows 10. Under normal circumstances I could choose either one with a GRUB entry and it would boot that OS without any issues.
Now I try to start Windows 10, and all it will do is show me a blinking underscore in the top-left corner and not boot, even after waiting 15 minutes.
I can still boot Ubuntu just fine.
How can I boot Windows?