Wondering where SharePoint 2007 lives in the registry? Probably not, but here you go anyways. 
Windows SharePoint Services (WSS) 3.0 is:
HKLM\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0\
Microsoft Office SharePoint Server (MOSS) 2007 is:
HKLM\SOFTWARE\Microsoft\Office Server\12.0\
The usual warnings of the registry apply. You edit the registry at your own risk. I will not be held responsible for any actions you take with your registry settings!
Warnings aside, it's pretty interesting to see what goes on under the covers!