[CentOS] No GUI with CentOS-7.2

When I re-booted my HP MicroServer into CentOS-7.2
I was given a text console.
When I run "startx" I get the response on screen [edited]:
=====================
[tim at alfred ~]$ startx
xauth:  file /home/tim/.serverauth.21307 does not exist
X.Org X Server 1.17.2
Release Date: 2015-06-16
X Protocol Version 11, Revision 0
Build Operating System:  2.6.32-220.17.1.el6.x86_64
...
Build ID: xorg-x11-server 1.17.2-10.el7
...
xinit: connection to X server lost
waiting for X server to shut down (II) Server terminated successfully (0). 
Closing log file.
=====================

No error is given in /var/log/Xorg.0.log.
It seems to find an appropriate ATI Radeon driver,
but it has the warnings
 (WW) Falling back to old probe method for modesetting
 (WW) Falling back to old probe method for fbdev
 (WW) Falling back to old probe method for vesa
Also it ends with what look like a problem with the USB mouse:
 (II) config/udev: Adding input device PIXART USB OPTICAL MOUSE 
(/dev/input/mouse0)
 (II) No input driver specified, ignoring this device.
 (II) This device may have been added with another device file.
 (II) config/udev: Adding input device PC Speaker (/dev/input/event5)
 (II) No input driver specified, ignoring this device.
 (II) This device may have been added with another device file.
 (II) evdev: PIXART USB OPTICAL MOUSE: Close
 (II) UnloadModule: "evdev"
 (II) evdev: HID 04f3:0103: Close
 (II) UnloadModule: "evdev"
 (II) evdev: HID 04f3:0103: Close
 (II) UnloadModule: "evdev"
 (II) evdev: Power Button: Close
 (II) UnloadModule: "evdev"
 (II) evdev: Power Button: Close
 (II) UnloadModule: "evdev"
 (II) Server terminated successfully (0). Closing log file.

Any advice or suggestions gratefully received.

Nb This is a remote machine, and I have not actually seen the screen
for several months, so this probably has nothing to do with CentOS-7.2.

-- 
Timothy Murphy  
gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin