New battery will not work vaio VGN-TX2HP

Question

Hi

I have purchased an after market battery as my old battery would only hold a charge for 1/2 hour. The part numbers match exactly the only difference is my old one says 7800mAh the new one 7200. The supplier has said it will work fine. Once installed the battery light flashes rapidly and it works the pc but is not charging.

Any suggestions......

Dave