I don't think anyone makes pc's with pci slots anymore, I'm having the same proglem.
I had to fire up an old Pentium 3 rig which was just a nightmare and didn't work in the end.
We too use the 6713 in each of our builds and motherboards with PCI slots are increasingly difficult to find. We are migrating to PXI, but that process will take years and I'm afraid we will have to stock up on motherboards in order to use the legacy boards.
Programming Data Acquisition and Control in Measurement Studio and Labwindows/CVI