Thank you
Your placemarks, and everything else is My Places, are the most
important and can be found in a file called myplaces.kml, which
usually lives here:
C:\Documents and Settings\<username>\Application Data\Google
\GoogleEarth
You could also right-click on My Places and choose 'Save as...' to
create a KMZ file, which you can copy to your other computer.
There's no export function for other settings, such as those in 'Tools
> Options' - you'd need to take a look art them and note down the
configuration.
:-)
Simon.