In terminal, enter the following (in several lines here, just for readability):
cd /System/Library/Frameworks/CoreServices.framework/
cd Frameworks/LaunchServices.framework/Support/
./lsregister -kill -r -domain local -domain system -domain user
cd Frameworks/LaunchServices.framework/Support/
./lsregister -kill -r -domain local -domain system -domain user
Log out and back in.
There is no step three.