Pulsing Blue Circle Behind Cursor - Cannot Use Keyboard

On powering up the blue circle behind the cursor pulses regularly together with the thumbnail and blue header which pulse alternatively and I cannot use the keyboard during one of these pulse cycles which occur about every 3 seconds which makes it impossible to type anything! I have 'solved' this occasionally by taking battery out, disconnecting power and opening in Safemode and then closing down and rebooting normally but there is no clear pattern to resolve this except to leave the machine permanently powered up - which works until the next Windows update and off we go again.