We bought a payne unit with a emc motor and compressor in November 2010. This past summer July 2012 the compressor froze up.
We went back to carrier and got another motor. When we installed it the compressor did not work and the motor made a humm noise.

A year and half old. Is it under warranty and do I fix it.

Sorry, if you fixed/worked on it yourself and you are not certified,, you probably have voided your warranty, if you are certified you should have a warranty