I'm having the pretty common "no screens found" on my Backtrack installation.

Tech Specs:

Backtrack 5 R2

Acer Timeline X 4830TG-6450
intel Core i5
14" LED backed LCD
NVIDIA Geforce GT540m with 1GB RAM and CUDA

The error in its hairy entirety:

X.Org X Server 1.7.6
Release Date: 2010-03.17
x Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-30-server x86_64 Ubuntu
Current operating System: Linux bt 3.2.6 #1 SMP Fri Feb 17 10:34:20 EST 2012 x86_64
Kernel commadn line:BOOT_IMAGE=/boot/vmlinuz-3.2.6 root=UUID-5b26f5fa-0c86-4a9a-a921-fc8dd3c713c1 ro text splash vga=791
Build Date: 25 February 2012 06:57:33AM
xorg-server 2:1.7.6-2ubuntu7.11 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman 0.16.4
Before reporting problem. check http:/wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) noticem (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var.log.Xorg.0.log:, Time: wed Jun 13 02:33:01 2012
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using config directory: "/usr/lib/X11.xorg.conf.d"
(EE) No devices detected.

Fatal server error:
no screens found

Please consult The X.Org Foundation support
at http://wiki.x.org
for help
Please also check the log file at "/var/log/Xorg.0.log" for additional information.

ddxxSigGiveUp: Cloding log
giving up.
xinit: No such file or directory (errno 2): unable to connect to X server
xinit: No such process (errno3): Server error.
root@bt:~# _