What to do with my Keurig B40

Ok, we got our Keurig B40 for Christmas 2009. We have really enjoyed it until it decided not to work correctly.

Sometimes we can get one cup of coffee, but then the machine makes a sounds like it might be reheating or something, and then it turns off by itself. This is getting very aggravating and not sure what to do. We have only used it for 3 months now and we do not use it everyday. What could be the problem?

I love the brands of coffee and also like the fact we can use the Folgers singles in place of the k-cups! It works just as well. But we can't use it if our machine is not working!