Are you using Avast anti virus ?
My laptop has Windows 8.1 Pro. It is a Dell computer. Today I went to my Tiles screen, tapped on my mail and it does a quick flash of a screen and then it is gone.
I then went to Settings/Change PC settings and it did the same thing when I clicked on Change PC settings. I can see the windows in my sidebar, but I cannot access them. The checking I have done says in order to fix my tiles, I need to do it through Change PC settings/Update & Recovery/Recovery/Refresh your PC w/o affecting your files/Get Started. Since I can't get to this, I obviously cannot fix the problem.
My computer knowledge is somewhere in the lower levels, but I am not completely incompetent.
Any suggestions will be greatly appreciated.
BTW. I can open some of the tiles, but not Google, Weather, Mail, People, PC Settings. These are a few of what will not open.