CENTOS5.5安装GNOME桌面，安装后，更新完软件包，重启，运行startx命令报错了：

X Window System Version 7.1.1 
Release Date: 12 May 2006 
X Protocol Version 11, Revision 0, Release 7.1.1 
Build Operating System: Linux 2.6.18-53.el5 i686 Red Hat, Inc. 
Current Operating System: Linux test.kinsun 2.6.18-274.18.1.el5PAE #1 SMP Thu Fe                                                                                        b 9 13:25:50 EST 2012 i686 
Build Date: 06 October 2011 
Build ID: xorg-x11-server 1.1.1-48.76.el5_7.5 
        Before reporting problems, check http://wiki.x.org 
        to make sure that you have the latest version. 
Module Loader present 
Markers: (–) probed, (**) from config file, (==) default setting, 
        (++) from command line, (!!) notice, (II) informational, 
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown. 
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Feb 20 13:21:20 2012 
(==) Using config file: "/etc/X11/xorg.conf" 
Parse error on line 29 of section Screen in file /etc/X11/xorg.conf

(EE) No devices detected.

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

进入/etc/X11/xorg.conf看了配置文件，应该是VGA驱动问题，之后尝试运行setup和system-config-display来调整都失败了：

[root@test ~]# setup 
Couldn’t start X server on card 0 
无法使用旧的配置启动 X 服务器，请试用一个新配置 
Couldn’t start X server on card 0 
错误，启动 X 服务器失败。 
Couldn’t start X server on card 0 
无法使用旧的配置启动 X 服务器，请试用一个新配置 
Couldn’t start X server on card 0 
错误，启动 X 服务器失败。

还好在chinaunix上看到一个帖子，重新生产一个新的xorg.conf配置文件，替换掉就可以了：

yum install xorg-x11-server-Xorg

Xorg -configure :0

cp /root/xorg.conf.new /etc/X11/xorg.conf

startx

之前我也曾运行过xorg -configure这个命令，X没有大写，所以提示“没有这个命令”，以为是包没有安装，输入yum install xorg-x11-server-Xorg，提示已经安装了，然后我以为连xorg的命令都失效了呢…