I have just bought a Lenovo IdeaCentre 730S all in one computer running fully up-to-date Windows 10 Home, along with a Logitech MK270 wireless keyboard and mouse.
Initially both mouse and keyboard worked correctly. Now the keyboard works intermittently sometimes not at all and sometimes with a delay of 1 second more between typing and the letters appearing on the screen. The mouse works correctly.
ControlPanel/Device Manager shows no problems and Lenovo Diagnostic software tells me that all drivers are up to date and that there are no hardware problems.
Any suggestions?