Alienware Desktop AW768 Logical Stuck Repeat Key (not physical issue)

Hi,

My sons Alienware desktop has developed a frustrating fault. 

Every once and a while the keyboard will repeat 1111111 even though the key isn’t pressed.

Unplugging for 10 seconds and then plugging the keyboard back in usually clears the fault, but there has been times that 1111 has continued even though the keyboard isn’t plugged in. 

Rebooting the desktop always resolves the issue.

We have tried:

Resetting keyboard back to defaults

Resetting the keyboard driver to original

Upgrading the keyboard driver to the latest version

Reinstalling Alienware command centre

Reinstalling Alienware control centre 

Removing Alienware control centre application completely fixed the problem for the a few weeks, but the problem has come back again. 

We have upgraded the BIOS etc through the Alienware app, but have now run out of ideas. 

My next step is to buy another USB keyboard, but this seems a rather drastic (and expensive) step. 

The PC is a very nice spec i7 Arora, but it is now 14 months old and I suspect this means out of warranty. It was bought in the UK.