I recently installed SP2 on a machine and ran into this error message everytime I attemtped to start the Windows Firewall:

Could not start the Windows Firewall/Internet Connection Sharing Service (ICS) on Local Computer.
Error 0x80004015: The class is configured to run as a security id different from the caller.

After some google searching I eventually found a thread describing the issue I was having. I have reworded the solution below.

  1. Click “Start” followed by “Run...”

  2. Type in “regedt32” and hit the enter key.

  3. Locate the key HKEY_Local_MACHINE\software\classes\appid\{ce166e40-1e72-45b9-94c9-3b2050i8f180} and highlight it.

  4. Click “File” and then “Export” from the File menu and export a copy of the key.

  5. Make sure the key mentioned in step 3 is still highlighted and delete it.

  6. Restart your computer and the Windows Firewall/Internet Connection Sharing Service should start automatically.