Failed drives or other things that cause the drives to not be bootable like unplugged or failed motherboards. It doesn't tell us much more than that.
I was playing a game on Windows 10 when suddenly my whole computer locked up. I had to do a hard shutdown. Now I can't run Windows 10 or Ubuntu.
I was dual-booting: when my computer started up I had to exit GRUB and then pick Windows 10 or Ubuntu. These are both on the same SSD.
I have an ASUS mobo and I have gone to the BIOS options page to manually boot. ( I should mention that when I press DEL or F2, I have to wait a good ten seconds before it will take me to the options menu.) I have tried the following:
Booting my SSD with GRUB, windows 10, and ubuntu. I just get a black screen with a blinking cursor.
Running Ubuntu from a USB drive: I'm getting these errors
"failed command READ DMA"
"exception Emask 0x0 SAct 0x0 action 0x6 frozen"
Using a system repair USB drive: Black screen with cursor.
SOLVED UPDATE:
I troubleshooted different parts of my computer and came to the conclusion that my SSD with my OS on it isn't working. I removed it and was then able to boot from ubuntu from USB.

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