Venue 11 pro 7140 hangs

My Venue 11 is on latest (I think) Win 10 version and seems to boot up normally showing all my desktop items OK. However when I click on any desktop item which is a shortcut to a web site it hangs indefinately. With desktop items that are short cuts to folders in internal memory it will open the folder OK but when I click on a file it will often display a message saying 'Windows is not responding'. Also when I click on the Wifi symbol at the bottom of the screen it displays an empty box when I know several Wifi connections are within range. I've run the Dell diagnostics accessed at start-up and all tests run without any reported problems. This problem started  few days ago after over two years use without any problems at all.