The aforementioned network card has a Realtek chipset and it uses the RTL8169 driver. It is available on the Win 7 driver update site. The adapter on my Gigabyte Ud4P mobo stopped working so I bought the Linksys card. I spent way too much time in google beforwe I was able to find this answer so I hope posting this here will help someone.

This worked great for me! World of Warcraft runs awesome on Windows 7

If you go to Realteks website, http://www.realtek.com.tw/downloads/ go to "Communications Network ICs then Network Interface Controllers then 10/100/100M Gigabyte Ethernet and then choose PCI Software and then "select all". Scroll half way down the page and you will find a Windows 7 32/64 bit driver!. Download the .exe INSTALLER, NOT just the driver, as it Windows 7 will not detect it if you try to update, you must have the installer to install all the drivers into Windows. During install it will say it could not find a device or not recommended etc but just continue. Go to device manager in the control panel and right click on the Ethernet not being recognized and update driver. Then choose browse my computer for driver software then let me pick and choose RealTek on the left window and PCI GBE Family Controller in the right window and hit ok. It works perfectly. I am now at my 25Meg download speed again.