Typing a capital letter crashes Mavericks

After installing Mavericks on my Macbook Pro, I cannot type a capital letter without the OS crashing. FYI: I'm writing this on my windows machine.

I first noticed it when I tried to install updates throught the app store. It asked for my password, and when I typed the capital letter *BAM* shutdown.

I tried to write an email in Gmail using Chrome and immediate shutdown after typing the firdt (capital) letter.

I tried the following programs with the same result: Notes, Safari, TextEdit, even Finder!

Is anyone else having this issue?

UPDATE: I just realised that all I need to do is hit the Shift key in a text field and the system crashes! This is crazy.