i was having problems with the battery on my hp laptop too, at about one month of age. sometimes it worked, sometimes it didnt. i emailed hp tech support, and this is what they told me to do. it fixed my problem.
right click on "my copmuter" "computer" depending on os,
go to "batteries"go to "ACPI control method battery" pr similar NOT THE POWER ADAPTER MAKE SURE UR DOING THE BATTERY!!!IMPORTNAnT!!!
right click on it and uninstall it, reboot the coputer...
that helped me...
also, maybe ur laptop came with a battery test utlilty, since mine did