We had a computer which could not run Windows Update because BITS would not start (error 2147014790, but could be others.)  MSE would not update either and the Event Log also had various other errors including “The IPsec Policy Agent service terminated with the following error: The requested service provider could not be loaded or initialized.”

Resetting the IP stack fixed everything:

1. Start the Command Prompt window as Administrator
2. Netsh winsock reset
3. Netsh int ipv4 reset
4. Netsh int ipv6 reset (if you use IPv6)
5. Restart the computer