plug in arduina and keyboard stops working

hi there

i have just installed Arduino onto a new computer. once i plug it in, my wireless keyboard stops working.
to be sure i have changed the batteries on the keyboard and tested it on another computer, so no problems with the keyboard (logitech mk320).
if i unplug the Arduino and move the keyboard usb plug to another port it resets and starts working again.

these are the steps to repeat the error/issue

  1. plug in Arduino
  2. keyboard stops working (mouse is a separate usb plug and continues to work)
  3. unplug keyboard
  4. replug in keyboard = Device manager: i get the error "device unknown" in the USB section
  5. unplug Arduino and keyboard
  6. replug in keyboard = working again (error gone from the device manager)

i have tried changing the COM port of the Arduinio but this does not help.
tried to update the driver for the usb but tells me its up to dateany help would be appreciated.

BR
mitch

i am using the Arduino UNO