[ubuntu-uk] input problem

[norman silverstone]

Xubuntu 12.04 -> boot,   no input possible from both keyboard and mouse 
buttons.

Ubuntu 12.04 -> boot,   only intermittent input possible from both 
keyboard and mouse buttons.

Windows XP Pro -> boot,   input from keyboard and mouse buttons as normal.

The problem occurred spontaneously with my PC. Suggestions please on how 
to troubleshoot this anomaly.

Norman