Thanks for the many good suggestions. Alt-Ctl-Esc and Alt-Ctl-F1 do not
work once the mouse has frozen. It is probably more like Xorg has
frozen. The mouse has not been changed and xorg.conf looks to be
correct. Legacy USB support was not enabled in the bios. It is
definitely an Xwindows/Xorg problem, because nongraphical system works
with no problem, even the mouse works if not running Xwindows.
Gary