I am very new to Linux but I followed a guide and installed version 5.0 on a Compaq P4 1.8 GHZ with 512 RAM so it's booting from the hard drive. It was working fine for about a week then one day it just doesn't boot to the desktop anymore.

On booting it takes me to the compaq login prompt - compaq login:
After logging in I get "Welcome to Knoppix Kernel 2.6.17"
On the screen above the prompt it says "Starting K display Manager: KDM. Not starting X display manager (xdm) it is not the default display manager"
(==)using config file: "etc/X11/Xorg.conf"
(EE) Open dev/fb0: no such file or directory
(EE) no devices detected

I type startx at the prompt and get the following:

Fatal server error:
no screens found
X10 fatal IO error 104 (connection reset by peer) on X server: "0.0"
after 0 requests (0 known processed) with 0 events remaining

What went wrong and how do I fix it? Thanks