TCP/IP is the network protocol used by the Internet. It's also the network protocol most often used in a local area network. The TCP/IP protocol contains multiple communications elements, each serving a unique and important purpose on any networked computer.
When your current TCP/IP driver is outdated and corrupt, impairing the performance of your network card, then your windows 7 system require reinstalling the TCP/IP network adapter driver on it.
If you are having problems with TCP/IP in Windows 7, then this windows 7 support blog you will find how to reinstall missing TCP/IP protocol driver on your windows 7 system. And some easy steps here -
Step1: Click on 'start' button then click on 'accessories' button.
Step2: Now right click on 'Command Prompt' and select 'Run as Administrator'.
Step3: Type "netsh int ip reset c:\resetlog.txt" in the Command Prompt shell, and then press the Enter button.
Don't restart your computer after prompt.
Step4: Now type "winsock reset" in the Command Prompt shell and press 'Enter' button.
Now its time to restart your computer & check that driver is properly installed or not.
Note: If you're using manually assigned TCP/IP settings, take notes as this will reset to the default 'automatically obtained'.