How to reinstall the TCP/IP protocol

This morning, the computer of my colleague sitting next to me broke down and went online without going to the Internet. I got the IT department to repair it. The answer I got was that I needed to redo the system. Recently, the IT department (especially the desktop group) has not handled many problems, so I took the initiative to help him see the situation and finally solved the problem. We hereby record the solution process and methods in case of the same problems in the future.

The main symptom is the inability to access the Internet and access (SET) of IP addresses.

1. The NIC indicator is normal;
2. Various protocols seem to be complete in the local connection attributes;
3. No static IP address or dhcp ip address can be obtained. The result of ipconfig is:

You can go to "my computer"-> "manage"-> "Device Manager" and choose "View"-> "show hidden devices ", check whether the IPsec Driver and TCP/IP protocol driver are in normal status.

If it is missing, you need to copy files from another machine and store the files to the problematic machine. My colleague's TCP/IP is gone, so I copied tcpip. sys from c: \ windows \ system32 \ drivers on my computer to his machine. However, the problem does not seem to be resolved after the restart.

Next, check the event log. There are many error events about TCP/IP:

Therefore, it is determined that the TCP/IP protocol is faulty, So we plan to reinstall the TCP/IP protocol. However, if you directly open the local connection property, you will find the TCP/IP protocol.The Uninstall button is in the disabled status. Refer to this articleArticle(Http://blog.sina.com.cn/s/blog_6133baa60100f1f7.html), re-installed the TCP/IP protocol, the problem finally solved. The installation steps are as follows:

Full uninstall of TCP/IP

Reference: http://support.microsoft.com/kb/325356

1. Locate the nettcpip. inf file in % winroot % \ INF, and then open the file in notepad.
2. Locate the [ms_tcpip.primaryinstall] section.
3. EditCharacteristics = 0xa0 entry and replace 0xa0 with 0 × 80.
4. Save the file, and then exit notepad.
5. In control panel, double-click Network Connections, right-click Local Area connection, and then select Properties.
6. On the General tab, click Install, select protocol, and then click Add.
7. In the select network protocols window, click have disk.
8. In the copy manufacturer's files from: text box, type C: \ WINDOWS \ INF, and then click OK.
9. Select Internet Protocol (TCP/IP), and then click OK.
Note this step will return you to the Local Area Connection Properties screen, but now the Uninstall button is available.
10. Select Internet Protocol (TCP/IP), click Uninstall, and then click yes. Restart PC.

Delete the following keys before reinstalling TCP/IP.

Run-> regedit
HKLM/system/CurrentControlSet/services/Winsock
HKLM/system/CurrentControlSet/services/Winsock2

Replace the 0 × 80 back to 0xa0, This will eliminate the related "unsigned driver" error that was encountered during the uninstall phase.

Return to "Local Area Connection"> Properties> General tab> install> protocol> TCP/IP

If"Extended Error"Occur, continue with the following steps:

Esentutl/G c: \ windows \ SECURITY \ database \ SeCEdit. SDB
Esentutl/R c: \ windows \ SECURITY \ database \ SeCEdit. SDB
Esentutl/p c: \ WINDOWS \ SECURITY \ database \ SeCEdit. SDB
Esentutl/G c: \ windows \ SECURITY \ database \ SeCEdit. SDB

Get back to your "Local Area Connection" properties
Choose install> protocol> TCP/IP and try again

You are done. Reboot your PC now.