I have been trying to change the screen resolution in xorg.conf and I edit the file as root, but somehow after rebooting the xorg.conf file is unchanged and the the changes I made are not there.

I i'm booting from a vmware hard drive.

any clue what is going on here?

I installed Knoppix 5.1.1 from the LiveCd to a vmware virtual hard drive. everyting works ok and changes done are kept after I reboot but the exception is this file XORG.CONF in the /etc/X11 directory that not matter what I change in it the next time I reboot the file is untouched, unchanged ... don't know why this is happening.