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.