Hi Richmac1 and welcome to LQ,
This issue can sometimes be a result of USB devices connected to the machine. I'd suggest trying systematically disconnecting USB devices to discover if one of them may be the culprit. (this is probably the easiest way)
When/if you figure out what is causing it, then you can search more specifically for a solution to that piece of hardware.
Just a thought, it may or may not be a result of USB devices.