Water or coffee is not dispensing
When I hit the brew button I notice that no coffee pours into the cup. If it does it comes out very slowly.
The water overflows instead of passing through the machine and dispensing coffee:
If the water or coffee overflows around the K-cup holder instead of dispensing, then your needles may not be penetrating the K-cup or the K-cup holder may be clogged. You can view our guide [here] on how to replace the top needle.
The water never makes its path to the K-cup:
If the water poured into the reservoir does not drain, it will not reach the K-cup. The drain on the Keurig may be clogged.
On my K10 the coffee was not coming out. After attempting to disassemble the Keurig (thanks to Roberto Maldonado for his guide) I discovered coffee grounds in the hose from the water pump, just above the needle for piercing the top of the K-cup. Long story made short, I never needed to disassemble the K10. I believe the problem was that my wife had purchased coffee pods that were not made of plastic. They had a paper top then a bundle of tightly packed coffee beneath. When these were pierced, they forced coffee into the top needle where it eventually clogged. The solution was to bend a paperclip and push it into the top needle to clear the clog.
BTW, my K10 is now 7 years old and is working perfectly.