if you want no prompt add this to the inittab (/etc/inittab)
*NOTE*
be sure that you have a free tty (no shell on tty7)
Syntax: <TTY>:<RUNLEVEL>:<TYPE>:<PATH> BAUD DEV
Example:
PHP Code:
7:23:respawn:su -c <UNPRIVED USER> "startx"
I think that a regular user can start the xserver, be sure that
PHP Code:
su -c <USERNAME> "startx"
works before trying the rest.