* Card ... Matrox G450 Dual-Head

* OS / Desktop ... Xubuntu XFCE vanilla install from Edgy LiveCD (along with all "update manager" recommended updates afterwards) 

* Problem ... libGL error everyone else was getting when trying to do 3d stuff

* Resolution ... Tried the Option "UseFBDev" "true" fix recommended

* Result ... X crashed and wouldn't load GUI, but terminal worked, so I undid the .conf file using Nano.  Was able to reboot back to GUI without issue.  (Haven't tried the .deb fix yet...was going to try it next)

Didn't see many Matrox G450 Dual-Head folks posting, so wanted to post my experience.  

Quick Andecdote...or "why I'm a Linux convert and don't complain about its bugs much".

I originally dual-booted Xubuntu with WinXP, because, like some Linux converts, I was tired of having to check in with MS to verify and activate software I had already paid money obscene amounts of $$$ for.  I wanted to see if the Linux grass was greener.  

The Xubuntu install was painless, and usage was smooth.  I was a little grumbly about having to rely more on command-line to do some things, but remembered how bad it was back in the MS-DOS days (using a command-line with really limited commands and batch functionality), so felt I could suck it up.  And, like some Linux'ers, have actually had fun learning about the guts of an OS...been so restricted with WinXP, it's kinda nice to be able to crack open and tweak anything and everything in Linux.

Anyways, while dual-booting, I was still pretty reliant on WinXP (since I was playing Tremulous on it, and couldn't get it to work well in Linux).  But, during a day of "routine maintenance" (you know, the 1 hour of reg-cleaning, defragging, temp-file deleting, etc), I decided to give the WinXP Disk Cleaner, which I had never relied upon before, a shot to clean up my temp files on the chance it finds something I had been missing the whole time.

It had an option to "Delete Win 98 Install Files", and I thought that was a good idea, since it was 50mb of wasted space...I was using WinXP afterall, so why keep the old Win98 install files?  While Disk Cleaner ran, the WinXP file protector kept popping up periodically asking me if I really, really wanted to delete this or that file.  Thought it was odd at the time, but kept clicking "yes".  After reboot, I found out the Disk Cleaner had totally wiped out critical boot files and .dll's.  I spent 2 days trying recovery, but after I got a message basically saying "so much crap was deleted you should just get your Sys Admin to reinstall", I gave up....literally.  I decided to give up on Windows from that point on, seeing as I had Xubuntu already installed.

I spent a few days tweaking Xubuntu, and finally got it to hook to my old Windows NTFS partition to try to salvage mp3's and such.  When I got it mounted, I was expecting a good 8 gb or so on it.  There was 250 mb (megabytes!)  Apparently Disk Cleaner had totally wiped major sections of my Windows partition (mp3's, Program Folders, Key Windows files and folders !!!)  I was so surprised by this I could only laugh out-loud.  Fortunately, I didn't have anything to irreplaceable on there, so I unmounted the Windows partition, gparted, and wiped the partition, re-formatting as ext2 for a nice installation of Damn Small Linux to mess with along with Xubuntu.

Moral of the story?  If I'm going to pay money to get screwed, I'd rather it be by a hooker then Microsoft.  While Ubuntu / Linux has its own flaws, I consider it the safe girlfriend I can bring home to show my parents, but one that can still have a wild streak when its alone with me...and I don't have to pay for it in the morning.