PCI Express 1.0a - base specification introduced in July 22, 2002
PCI Express 1.1 - base specification introduced in March 28, 2005
PCI Express 2.0 - base specification introduced on January 15, 2007. First PCIe 2.0 capable chipset motherboards appear on the market on October 21, 2007.
The nForce4 chipset, of which the nForce 430 is part of, was released in October, 2004 and implements PCI Express 1.0a.
The release date of the HP Pavilion a6130n was 6.5 years ago. That's well before the PCI Express base specification 2.0 was introduced. The HP Pavilion a6130n's motherboard uses the nForce 430 chipset.