I read previously on other threads that installing ubuntu on some newer machines can cause the problems with the bios, where 'Ubuntu' will write over the bios, and cause the machine to end up being a brick.
How do I know if I'm safe?
You're getting a bit mislead here.
The problem was with certain systems that use UEFI. It has since been solved. Other systems were (and remain) unaffected. So, if your system isn't from Samsung and doesn't come with Windows 8, you're likely in the clear.