I had a similar problem, which I just found the solution. If you have an nForce nVidia Network Controller on your motherboard, then you need to update your driver.
http://www.nvidia.com/Download/index.aspx?lang=en-us
1) Go to the website above, select "nForce" in the product type
2) select the appropriate "series" for your motherboard. If you don't know the series, then go to step 2a, otherwise proceed to step 3.
2a) (note: if you are not sure of the series, then first click "Motherboard drivers" in the option 2 section. But don't select the driver, here, just find out the series. Then go back step 2
3) Select download type "Driver"
4) In Operating system, select 'Wndows 7" with the appropriate 32 or 64 bit.
After...