Linux Mint does not boot :(

Hey,
I am completely new to Linux.
The first time after installing, everything booted fine, but now I get this:

http://lulzimg.com/view/a3939ccb.jpg
What to do?
Thanks!
EDIT:
When I type “xstart”, this occurs:
http://lulzimg.com/view/51f37be3.jpg
Answer #1
the ‘fatal error’ msg means you are going to need to re-install the mint os.