Try to update the BIOS of the computer by going to the website and seeing if there is any support for your computer. Usually there is a new BIOS version and could be why it does not recognize it. Had the same issue with a laptop from Dell that my friend could not make the computer detect the new battery he bought.
I recently bought a new battery for my Aspire 3680 notebook. The notebook tells me that no battery is detected..so I exchange the battery for a new one thinking I got a bad one. Second battery same problem. But the notebook does recognize the old battery.