1st your MB has the G41 chipset, which has the pcie1.1X16 slot.
http://www.intel.com/content/www/us/en/chipsets/mainstream-chipsets/g41-express-chipset.html And the GPU is the pcie3.0X16 version. In theory the pcie3.0 GPU is backward compatible to the pcie2.0, 1.1, or 1.0 version. But in the real world the pcie2.1/pcie3.0 GPU has problem with some of the MB with pcie1.1 slot, here is from wikipedia: "Unfortunately, the increase in power from the slot breaks backward compatibility between PCI Express 2.1 cards and some older motherboards with 1.0/1.0a, but most motherboards with PCI Express 1.1 connectors are provided with a BIOS update by their manufacturers through utilities to support backward compatibility of cards with PCIe 2.1."
http://en.wikipedia.org/wiki/PCI_Express
And you are better to double check the BIOS version and date, how to
http://www.wikihow.com/Check-BIOS-Version if the BIOS date is after 2009, you are fine, if it is before 2009, you should update the BIOS first. If you can't find the BIOS that is after 2009, you are better to buy the nvidia gpu. because that problem is only for the AMD GPUs ( pice2.1 or pcie3.0 ).