And you have try'd the calculator inside Win 7 ?
I never used my self but it is there.
I use the Windows Calculator many times most days, but I never investigated the view menu very closely. I just did and was surprised to see that it can expand into a converter. Too bad it doesn't retain the From and To fields to the last used measure. It reverts to Angstroms when closed and reopened. This means extra steps to set up for a conversion.
I think the Google converter might be okay now that I an running Google Chrome. I can bookmark a link and place it on the easy access favorites bar. I always have my browser open, so one click and it opens and a quick entry and I have the conversion.