Why did I seem to lose my Calculator and Clock programs?

[JohnJSal]

I don't know what caused this, but suddenly it just started happening. When I click on Calculator or Clock in the Windows Start Menu, nothing happens, as if they just aren't installed anymore. I've also noticed that a couple of programs have a black line underneath them. You can see it here in the screenshot: https://snipboard.io/nCh47K.jpg

When I click the Calculator shortcut button on my keyboard, a little window pops up that says "You need an app to open this."

Anyone know how I can fix this?

Thanks!