As far as the drivers are concerned, you might try the process I detailed in a post in the DX58SO2 - Trouble thread. http://communities.intel.com/message/125206#125206 msg 203 on page 14. The same over-ride switch might work.
Interesting trick, but it didn't work. I can "sometimes" make the problem appear by restarting my rig. After two restarts, the same problem manfest itself. Can someone check what DeviceManger says is the installed version of your NIC driver? Version 126.96.36.199 doesn't seem right to me after I download and installed a file marked v16.2.
"16.2" is the Intel(R) Network Connections version number. Not all components are updated with each new software version. The driver (e1q62x64.sys) for your network connect has not been updated since 2010, which is why you see a difference in the dates. Drvier version 188.8.131.52 was the latest driver version. That is why you never see any change to the driver version when you install the latest software package.
I am not familiar with the desktop boards, and I do not have an idea as to why your connection stops working, and then works again after you uninstall and do a new install of the driver. Maybe someone else has some ideas.
By the way, the driver history page lists all the driver versions in the most recent releases. I know that Intel Network Connections version 16.3 will not have an updated e1q62x64.sys driver, but keep an eye on the history page for an updated driver. I know an update is planned for later on this year. I do not know if the driver update will affect the issue you describe, but you should probably give it a try.
Mark is right. I just checked my network driver and it is 10.1.9.0 dated 4/7/2010 on one adapter and 184.108.40.206 on the other. I guess I only had one adapter enabled when I loaded the drivers. I had forgotten that the Intel(R) Network Connections version number is not necessarily the driver version. Sorry to run you down the road on a wild goose chase!