Hi
You said; after booting, the next day you had no diplay,
Well right after booting from lilo, X is not working and
there should be some readable messages flying by.
Does booting into runlevel 3 or single gives you a
display? If it does, you should be able to modify your
XFconfig-4 by hand. If not; i think, its a bootloader or kernel
related thing. (try for inst. vga=normal in lilo, or as boot-
option, after hitting esc from lilo; runlevel 3 vga=normal)
For RH 7.3 and Nvidia related stuff try this link for
some hints;
www.nvnews.net/forum/