Go to this link and click "downloads and software": Intel® Desktop Board DG31PR Product Specifications
There, you will find all the drivers, and latest bios, for this relic of a board. I would make sure the bios is updated, and I would reset the bios to defaults.
Now, it could be that this board has a custom bios, in which case there is nothing you can do. So, to verify that, provide the bios string.
Also, XP? Not supported in more than four years. So, if it does not work, then it does not work.
Note that this board is also unsupported, but a few of us here are familiar with it.
Current BIOS version PRG3110H.86A.0071.2010.0318.1704
Copy Right 2009 Intel Corp
BOARD Version AAD97573-205
As far as board being a relic, I agree with whats on the market today. I figure a 2ghz board would be faster than my 1.4ghz I built few years ago. Can you tell if that's the most up to date BIOS available?
Yes, in the first link, if you click on "downloads and software", you will see all the drivers and bios for your board. 0071 is the latest.
As I said, in the bios, RESET to defaults.
Here is the bios: Download BIOS Update [PRG3110H.86A]
You should use ONLY the drivers here, on this link. I hope you have not gone to some place on the net to get drivers.
If it were me, I would get a copy of XP SP3 (if you insist on XP), and copy the LAN driver on the link I provided to a USB stick. I would do a clean install of XP SP3, wiping out all existing partitions on the disk. As soon as the system was up, if there was no LAN driver installed by the XP install,or to update the one XP installed, I would install the one you put on the USB stick. Here is the LAN driver:
If, at that point, you do not have LAN access to the net, STOP. Do not do anything else. Come back and report your findings.
Only slightly better. It is a ten year old board:
I had, and still have, some of this old hardware. I had to face the reality of it getting old, and of not much use software-wise. I can still get leaded 108 octane gas for my 1950s car, and drive it on the interstate at 60mph (100 km/h for our metric friends) without a problem. On old hardware, you will not get much mileage in today's world.