For 'startx' fatal error, I am not able to describe much, because i have removed the OS from the server. The server i am using is a DELL PowerEdge 840 - Pentium D 2.8Ghz Pro 915 - 1GB DDR2 ECC - C4 RAID 1 Card - 160GB SATA 2 As mentioned in my first post. Basically I get the error with these few easy steps 1 - Fresh Installed CentOS 5 2 - Use yum to install Yumex first 3 - Use yumex to install FreeNX - and follow the instructions from http://wiki.centos.org/FreeNX 4 - After installation, I go into /usr/bin/nxserver to --adduser root 5 - Then I --passwd root and set a password. 6 - Later I went to /etc/nxserver and copy a copy of client.id_dsa.key to my thumbdrive. 6, A - <<Add>>, I also config my server to static ip 192.168.1.5 before i reboot the server 7 - I reboot the server after that, and leave it aside without local login anymore. 8 - I setup my NXClient and copy the .key before i log into the server with the root account 9 - I get a successful login. 10 - Now I will reboot the server through the remote NX session. 11 - I go to System -> Log Off -> and select Reboot. 12 - The server reboot, and my NX client was cut off with a violent error, saying something like "Connection has been disconnected" etc. 13 - After the reboot, I can no longer log into server with NX anymore. The client will prompt error msg, like what PASTED in the first post. 14 - I then turn back to local login, and here GOES~ the GNOME, i am left with only console login. This is exactly how to recreate the freenx error for my case.