Reverting back to apache2 from lighttpd: have issues

[John Foster <jfoster81747@verizon.net>]

I have been trying to get lighttpd to run as my web server but was not
able to get it properly configured. I kept getting an error message
saying that localhost was not configured properly and I could not use
the simple browser url  "http://localhost to open the server. I decided
to reinstall apache2 & as I had totally removed ALL of apache2 even any
references to it; the new install was pristine from Debian stable. It
fired up but I'm still getting the same error when I try to use
localhost. I use localhost as my editing server for the mediawiki
installed there /var/www  directly into that directory. Any ideas what I
have screwed up with my system that will cause this. Also the server is
not delivering the actual website either.
thanks
john