Is there a driver needed to recognize the battery?
Can you start your computer after first turning it off and removing the AC adapter?
1) update your BIOS if it's out of date
2) look under Drivers and Software for your laptop to see if there are any drivers or software updates that might recognize the 3rd party battery
3) Turn off your PC, unplug it and RESEAT your battery to be certain it's definitely snapped in there (I don't see how it could not be though)