How do I change my video card (GeForce 3 - 6600) - more info

I am running FC3.
Xorg 6.8.2
Had Asus Geforce 3 8200 Deluxe 64MB Analog out
Added Asus Geforce N6600 AGP 256MB Digital out

Shutdown the computer. Removed G3, put in 6600.
Started up.  Hardware changed detected, removed
G3 configuration. Tried to run X. Computer hung.
Tried reinstalliing latest Nvidia drivers, nope.
Tried coping config of similar card into xorg.conf
from net.  Nope.

Does anyone know what my config should be?
Is there a tool I can run that comes with
FC that will autoconfig my file (that does
require X already running)? Other suggestions?

I know the 6600 is already supported in the 70
series drivers.

thanks

Stephen

More Information:

I put in: Option      "ConnectedMonitor" "DFP" because
I am now running my Samsung 191T via DVI.

I have X running. I changed my Identifier in the xorg.conf
file but didn't change the reference in "Screen". After
chmod'ing and chown'ing the /dev/nvidia* files I am able
to glxgears.

Next test was Doom3.  Monitor signal kills and I suppose
a kernel panic because I can't ssh in.  Have to reboot.

After I changed 0/FlatpanelScaling[DFP-0]=0 to 1
in /home/user/.nvidia-settings-rc, I was able to see the
user interface loading screen of Doom 3.  I even hear
the ID logo sound in the background.   Doom 3 locked
up, however I was able to ssh in to reboot.  Thus I suspected
a problem with my Doom config, so I tried Enemy Territory,
but it kernel paniced.

Here's a sample from my xorg.conf:

Section "Monitor"
       Identifier   "Monitor0"
       VendorName   "Monitor Vendor"
       ModelName    "SyncMaster"
       DisplaySize  380        310
       HorizSync    30.0 - 81.0
       VertRefresh  56.0 - 85.0
       Option      "dpms"
EndSection

Section "Device"
       Identifier  "NVidia6600"
       Driver      "nvidia"
       VendorName  "NVidia"
       BoardName   "ASUS N6600"
       Option      "ConnectedMonitor" "DFP"
       Option      "RandRRotation"
EndSection

Section "Screen"
Identifier "Screen0"
Device "NVidia6600"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 16
Modes "800x600" "640x480"
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
EndSubSection
EndSection