I had a problem where the network card driver in Windows 7 was faulty. It is a known issue with the Asus on-board ethernet card. The fix was to install the Vista driver, but doing that is easier said than done.
I first tried to just install the driver over the top of the old one which looks like it worked but didn’t replace it. I then tried to un-install the driver via the Device Manager. You then have to reboot for it to take effect, but on boot Windows detects the hardware and installs the same driver again!!!
To get around this you need to turn off hardware detection. You may also need to allow unsigned drivers (a new requirement in Windows 7, not Vista). Both of these are set via Group Policy.
Click Start -> Run -> gpedit.msc (and push Shift + Enter to run as admin) Navigate to Computer Configuration -> Administrative Templates -> System -> Device Installation -> Device Installation Restrictions Set ‘Prevent installation of devices not described by other policy settings’ to ‘Enabled’ Set ‘Allow administrators to override Device Installation Restriction policies’ to ‘Enabled’
Then go to the Device Manager (<Right Click> Computer -> Manage -> System Tools -> Device Manager) and un-install the driver. Then reboot. The driver should not be installed by Windows. Go to the Device Manager again and it will be listed under unrecognised device or something. Now right click on the device and then ‘Install Driver’ and give it the proper device driver.