X server already running on display :0

[Leslie Jensen]

I have a problem that I do not understand.

At the prompt I give the command startx

I get a message that /usr/local/bin/startxfce4 does not exist.

Copy the file from another system and I get

X server already running on display :0
/usr/local/etc/xdg/xfce4/xinitrc: Can't open 
/usr/local/etc/xdg/xfce4/xinitrc: File or catalog does not exist

I have not knowingly made any changes to this machine.

Any suggestions?

Thanks

/Leslie