USB optical mouse suddenly not working

[Kirtis Bakalarczyk]

After dist-upgrading my breezy installation today, X stopped working. 
A quick glance at the log file revealed:

(**) Option "Protocol" "ImPS/2"
(**) Configured Mouse: Device: "/dev/input/mice"
(**) Configured Mouse: Protocol: "ImPS/2"
(**) Option "CorePointer"
(**) Configured Mouse: Core Pointer
(**) Option "Device" "/dev/input/mice"
(EE) xf86OpenSerial: Cannot open device /dev/input/mice
        No such file or directory.
(EE) Configured Mouse: cannot open input device
(EE) PreInit failed for input device "Configured Mouse"
(II) UnloadModule: "mouse"
(WW) No core pointer registered
(II) XINPUT: Adding extended input device "Generic Keyboard" (type: KEYBOARD)
(II) XINPUT: Adding extended input device "NVIDIA Event Handler" (type: Other)
No core pointer

Fatal server error:
failed to initialize core devices

And indeed it's correct, there is no entry in /dev/ for my mouse any more.
The mouse is lit up fine and a lsusb reveals:
Bus 001 Device 002: ID 046d:c016 Logitech, Inc. Optical Mouse

.. so i think the mouse is working fine.  A little help here?

KIRT

--
pub   1024D/742050ED 2005-06-04
      Key fingerprint = 94BB 9D18 28A6 6267 8299  3EC9 4696 0626 7420 50ED
:wq