LAN is not recognizing Internet port

I agree with what anjana03 stated.

If you are plugging in your Ethernet cable to your computer in the I/O area, then you are using the Onboard LAN.

(Onboard - On the motherboard.

I/O area. Input/Output. This is where a mouse and keyboard, are usually plugged into the back of the computer. The shiny rectangular metal plate is an I/O Shield)

If this is where the Ethernet cable plugs into, try reinstalling your LAN drivers, as suggested by anjana03. These Drivers will be located on your Motherboard CD. They are also located at Intel Support.

This is Intel Support, and the Tools and Software page, for the Intel DG31PR desktop motherboard,

http://www.intel.com/products/desktop/motherboards/dg31pr/dg31pr-tools.htm

Scroll down to the heading - BIOS and driver updates
Click on Driver Updates, below this heading.

If updating your LAN driver doesn't fix your problem, then as suggested you should buy a LAN expansion card, and install it in the appropriate slot on your motherboard. (PCI, or PCI Express x1 slot. Depends on the type of LAN card. You have a PCI Express x1 slot, and a PCI Express x16 slot. The PCI-E x16 slot is used for graphics Only. The PCI-E x1 slot is the one you want)

If you do not have the Motherboard Manual for your DG31PR, here it is,
(PDF form)

http://www.intel.com/support/motherboards/desktop/dg31pr/sb/cs-027915.htm

Re instal lan softwere one time from your bord softwere. inbuilt lan if not work put other lan card in bord pci slot and and instal it can help you

Then you have reinstall *********** boards drivers from its cd.