Before some days I had issue with the finder due to improper shutdown. Then I've goggled for the same issue & I find below solution. Not sure but its worked for me.
I've rebuild LaunchServices database in Leopard with "lsregister". May be "lsregister" have different location in another version. Locate & run below command from Terminal.
You can use "spotlight" to open terminal as finder is not working.
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.fram ework/Support/lsregister -kill -r -domain local -domain system -domain user
