Winsock2 key corrupted?

Source
Manual steps to determine whether the Winsock2 key is corrupted for Windows XP users

To determine if the symptoms are caused by a problem with the Winsock2 key, use one of the following methods.
 

Method 1: Use the Netdiag tool

To use the Netdiag tool, you must install the Microsoft Windows XP Support Tools. To do so, follow these steps.
Notes

• If you already have Support Tools installed, go to the second procedure in this section.
• If you do not have Support Tools installed and you do not have the Windows XP Setup CD, go to Method 2.

1. Insert your Windows XP Setup CD, and then locate the Support\Tools folder.
2. Double-click the Setup.exe file.
3. Follow the steps on the screen until you reach the Select An Installation Type screen.
4. On the Select An Installation Type screen, click Complete, and then click Next.

When the installation is complete, follow these steps:

1. Click Start, click Run, type Command, and then click OK.
2. Type netdiag /test:winsock, and then press ENTER.

The Netdiag tool will return the test results for several network components, including the Winsock. For more details about the test, use /v at the end of the netdiag command:  

netdiag /test:winsock /v 

Method 2: Use the Msinfo32 program 

Note Use this method only if you do not have a Windows XP Setup CD and you do not have Support Tools installed.

1. Click Start, click Run, type Msinfo32, and then click OK.
2. Expand Components, expand Network, and then click Protocol.
3. You will have ten sections under Protocol. The section headings will include the following names if the Winsock2 key is undamaged:
   • MSAFD Tcpip [TCP/IP]
   • MSAFD Tcpip [UDP/IP]
   • RSVP UDP Service Provider
   • RSVP TCP Service Provider
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   • MSAFD NetBIOS [\Device\NetBT_Tcpip...
   If the names are anything different from those in this list, the Winsock2 key is corrupted, or you have a third-party add-on, such as proxy software, installed.

If you have a third-party add-on installed, the name of the add-on will replace the letters "MSAFD" in the list.

If there are more than ten sections in the list, you have third-party additions installed.

If there are fewer than ten sections, there is information missing.

Note These entries represent an installation with only the TCP/IP protocol installed. You can have a working Winsock and see additional entries if another protocol is installed. For example, if you install NWLink IPX/SPX, you will see 7 additional sections, for a total of 17. Below is an example heading of one of the new sections:

MSAFD nwlnkipx [IPX]

Also, each of the new sections that are created by installing NWLink IPX/SPX start with "MSAFD." Therefore, there are still only two sections that do not start with those letters.
 

If the Netdiag test fails, or if you determined that there is Winsock corruption by looking at Msinfo32, you must repair the Winsock2 key by using the steps in the next section.
To have us reset the Winsock settings for you, go to the "Fix it for me" section. To reset the Winsock settings yourself, go to the "Let me fix it myself" section.

To reset the Winsock settings automatically, click the Fix it button or link. Click Run in the File Download dialog box, and then follow the steps in the Fix it wizard.

Fix this problem
Microsoft Fix it 50203

Note this wizard may be in English only; however, the automatic fix also works for other language versions of Windows.
Note if you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.
Next, go to the "Did this fix the problem?" section.

Read the procedure for Vista