Step #1
These steps are copied from 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. Edit the Characteristics = 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:windowsinf, 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
succesfull uninstallation of TCP/IP will remove numerous keys from the registry including
HKLM/system/CurrentControlSet/services/tcpip
HKLM/system/CurrentControlSet/services/dhcp
HKLM/system/CurrentControlSet/services/dnscache
HKLM/system/CurrentControlSet/services/ipsec
HKLM/system/CurrentControlSet/services/policyagent
HKLM/system/CurrentControlSet/services/atmarpc
HKLM/system/CurrentControlSet/services/nla
These represent various interconnected and interdependant services.
For good measure you should delete the following keys before reinstalling TCP/IP in step #2
HKLM/system/CurrentControlSet/services/winsock
HKLM/system/CurrentControlSet/services/winsock2
Step #2
Reinstall of TCP/IP
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Following the above substep #13, replace the 0×80 back to 0xa0, this will eliminate the related “unsigned driver” error that was encountered during the uninstallation phase.
Return to “local area connection”> properties > general tab > install > Protocol > TCP/IP
You may receive an “Extended Error” failure upon trying to reinstall the TCP/IP, this is related to the installer sub-system conflicting with the security database status.
to check the integrity of the security database
esentutl /g c:windowssecurityDatabasesecedit.sdb
There may be a message saying database is out of date
first try the recovery option
esentutl /r c:windowssecurityDatabasesecedit.sdb
this did not work for me, I needed the repair option
esentutl /p c:windowssecurityDatabasesecedit.sdb
rerun the /g option to ensure that integrity is good and database is up to date.
Now return to the “local area network setup”
choose install > protocol > tcp/ip and try again
