X11 broken by weekend upgrades? ("can't find default font")

[rossini@biostat.washington.edu (A.J. Rossini)]

I've got a nasty case of broken X configuration, due to a recent
upgrade over the weekend ("Can't find default font, Fixed").  I might
added a number of xfonts (xfont-jmk? and some Chinese, since I'm
learning) and things aren't working.

Any thoughts?  

Please cc me directly; this is the first time since 1990 that I've
broken an X configuration this badly and the usual things havn't
solved the problem!

best,
-tony