Recently, I had some strange problem with a network interface inside Windows 2008. I managed to solve my problem only by reset the whole network IP stack in Windows 2008 (Those steps work in Windows Vista and Windows 7 as well). Here are steps:

• Go to the Start Menu, type cmd and right click or (Ctrl + Shift and hit Enter), and select "Run As Administrator"
• Type the following commands, each followed by pressing enter.

• ipconfig /flushdns
• nbtstat -R
• nbtstat -RR
• netsh int reset all
• netsh int ip reset
• netsh winsock reset

Alternatively, another helpful command that i mentioned in one of my old posts:

• netsh interface tcp set global autotuninglevel=disabled