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I'm going to give you the short of it, since trying to register with this site has deleted what I spent 10 minutes typing.

I'm dual booting ubuntu 13.04 and windows 8. Usually, when I try to start ubuntu, I get a black screen with something to the tune of:

kvm: Disabled by BIOS Bad IO at port [x] Bad IO at port [x] etc.

When this happens, my computer fan will speed up, and the computer turns off after a time.

In addition, I need to change my BIOS settings to switch OSes. I don't know if this is normal. Windows 8 won't boot on legacy, Ubuntu only boots on legacy.

Also: Sometimes windows won't boot. This has only happened after installing Ubuntu.

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Probably your Windows is in EFI mode, and Ubuntu in Legacy mode. You need to convert Ubuntu into EFI mode. See

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