Battery Issues.

My MacBook wont recognize a battery. It will run off the battery power if i use a fully charged battery, but it wont charge it or even recognize it's there, I get the little battery with the x in it instead of telling me what percentage is left on the battery. Any ideas, I have tried with 2 different batteries also. Neither work.

Thanks

good news first your battery seems fine. try this.
Apple Portables: Resetting the System Management Controller (SMC)

And then be nice to it, do this