There's something wrong with your display driver. It can probably be fixed:
Press <CTRL><ALT><F2> [ In the same way as you'd do a ctl-alt-del on windows
You'll get a text login screen.
Type your username then press ENTER
Type your password then press ENTER (your password may not be shown on the screen, at all. So just type it OK?)
Now type the following command:
sudo dpkg-reconfigure xserver-xorg
Give your password again.
Answer the questions.
When you have finished type
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