Q: Tonight I brought up Linux, and tried to start the X server. It hung my machine. I ran Xconfigurator, to see if that was the problem. I found that my video card (Matrox Millenium G200 8MB AGP) is listed, but the associated file XF86_Matrox_Com was not present.
A: When you say X hung, did it lock the machine up? What happened? Did you try control-alt-key-pad-plus or control-alt-backspace?
Your card is new enough that Xconfigurator doesn't understand the G200, or the XFCom_Matrox server. Depending on when your machine shipped, there may be an xf86config program that will work, but it requires you answer the question about the symlink correctly.
If you have the orginal /etc/X11/XF86Config file, then try this:
-replace your current Xf86Config file with the orginal.
-'rm /etc/XF86Config' (startx checks here first)
-'ln -sfi /usr/X11R6/bin/XFCom_Matrox /etc/X11/X'
-'ln -sfi /etc/X11/X /usr/X11R6/bin/X'
- startup X "startx"
-if blank screen hit control-alt-keypad-plus . (This cycles thru your modes try at least 4 times)
-if that work doesn't try control-alt-backspace. (This should kill the X server)
If you don't have the orginal XF86Config file, try the above, anyway.
 That statement is not longer true: The Matrox G200 series is now long out of production, in fact, but this article serves to illustrate a general approach to dealing with such problems.