Please help. Mouse Keyboard issue.

Hi Hope someone can help.
I've been using this G4 for a couple of years now. Just recently it's been locking up every few minutes. Here's the thing, If I unplug the USB mouse or keyboard it frees up again. I have tried:

A different keyboard.
A different mouse.
Tried both USB ports and the rear of the CPU.

When it locks up I can still use my keyboard shortcuts sometimes but not always. Very Strange.

I don't think it's hardware but don't know enough about it to be sure.
It happens every few minutes. Anyone have any idea?

Many thanks in advance

Darren

 

Hi thanks for your reply. I have tried another keyboard and another mouse. I have carried out no maintenence other than running Nortons Utilities and Disk Warrior. I don't know much outside of running my applications so I know nothing about 'repair permissions', but I'll do a search on it and try it.
Many thanks.