[X4U] Resetting Software Update

[Chesley Powell]

I recently purchased an iMac and used the start up assistant to move 
all my "stuff" from my PowerBook over to the iMac.  Worked great, a 
nice feature!!  However, the software update under the Apple drop down 
menu does not work without going to the System Preferences and 
initiating the Software Update there.  I assume there if a file 
somewhere that came over from the PowerBook that needs to be deleted.  
Any suggestion would be appreciated.