Frustrating day with Windows 10

I've been using Windows 10 for a while now (as well as OS X), but today it developed a serious problem - the Start button won't work, nor will searches and other things. So far I've spent over 10 hours on it without fixing the problem, and web searches suggest others have had the same problem. So with all the time wasted on the computer, it has to be an emergency Blip for the day.