Stuck "+" key but keyboard is not the issue

[Rogercrudeoil1]

My desktop is constantly typing "+" without stopping.  The keyboard is not the issue, it still happens when disconnected.  I have swapped out the keyboard as well.  I have activated Filter Keys in Keyboard setting to stop the repeat "+" but every keystroke is followed by a "+"  .  

[BeemerBiker]

Sound strange like a USB port problem.

I do not have a system like yours but possibly the following might work

Bring up the BIOS and if possible disable the FRONT USB ports and leave the BACK USB ports enabled.  If that does not work then do the opposite.

ie: try to disable the port that is causing the problem with your usb keyboard.

OTOH if the problem only occurs in windows then  add a new user and log in using the new username and see if the problem goes away.

[crudeoiltrader1]

Thanks BeemerBiker for taking the trouble to answer my query.

I am an IT novice.  I not sure its the ports thats the issue and I dont know how to bring up the BIOS to follow your instructions.

What I did do is uninstall the keyboard drivers, rebooted and they were automatically re-installed.  This did the trick, BUT the next day the problem came back.  Would this provide a clue as to my next step? Many thanks