I've just made the big change, making the WP site the active part of the site, so that if you just type in the domain, you go to the WP pages. Whew! Still a little slow, and I have an urgent request in to the ISP guys to figure out why that is.

Anyway, one thing I haven't figured out (among many!) is how to get the search function to reach backward and search the old HTML files, not just within the WP database. Those old files were searched in the past with a Google custom search. Should I just put that in place in lieu of the built-in WP search widget?

Can I put in some code to force the WP search to cover the whole site, old and new?

You would have to use the Google search for this. WP doesn't know of the static HTML sites. A plugin would have to scan your files and put them into the database. I don't think there's a plugin that would do this

How do I configure a search like that and would you still remember how the plugin was called?

I ended up using Google custom search for this.

Is that a plugin and can you configure it to search accross different sites, we have a main domain called www.tribe-online.de while the archive is called archiv.tribe-online.de

Hody... If you do a search for "Google custom search" either though Google or at wordpress.org you will get plenty of info on this.