My macbook crapped out and now says the internet and server have failed. I don't know what to do!!! help!!

Last night my macbook (Mac OS X, Build:10J567), randomly shut off when I was in the middle of using it. And now every time I turn it on, my background has been changed, a pop up says my computer's clock has been set to a date before January 2008, and my internet wont work. So when I go to fix it, it says my internet has failed and so has my server. I know our wireless internet in the house is fine, because our house computer still works. But my laptop isn't! Can anyone help me? 😟