Pavilion g6 shuts down when battery is around 40%

Hi,

Recently my notebook dies when my battery is around 40%. When I plug in the netadapter it works fine, it starts again (via the Windows Error Recovery screen), says that the battery is 40% charged  and recharges the battery to 100%. 

I already cleaned al vents to prevent heating issues, I updated my BIOS to the most recent version and I calibrated the battery.

When browsing through these forums I found another person with this problem, but without a solution. (http://h30434.www3.hp.com/t5/Notebook-Lockups-Freezes-Hangs/Laptop-dies-suddenly-HP-Pavilion-g6/td-p/2445531)

Is anybody familiar with this problem and/or knows how to fix it?

It concers a Pavilion G6, productnumber: B1L80EA#ABH, running Windows 7 64 Bits,  Service Pack 1.

Thanks in advance!