How do I fix my Xbox 360 S problem?

Okay well I was playing my Xbox for hours today, takings breaks of course, but the last time I turned it on to play it, I received the 'red dot' where you push to turn it on. So I shut it off, waited a few seconds and turned it back to to see it turned green, but now my Xbox takes much long to go through the whole 'Xbox logo swooping and circular video and then stops there, I never make it to the Dashboard....any help??