CloseAll is a simple tool which can close all applications with a click.
Launch the program and it lists all the running programs with desktop windows. You can click a button to close all these windows, or deselect particular apps you'd like to stay open.
This is safer than it sounds. The program only works with top-level application windows, for instance, so it won't try to close down system processes, your antivirus program, or anything else that lives in the system tray.
And the method used to close applications is relatively gentle, so if an application has work which you haven't saved then it shouldn't close immediately: you'll first see the usual message asking if you want to save your data. (That's the idea, anyway, but we'd recommend you test it with your own applications, first, just to be sure.)
Changelog for CloseAll v2.1 (June 1, 2017):
Support for Windows 10 32-bit and 64-bit
Now CloseAll can enumerate and close Metro applications
Installer is DPI aware now and looks much better with scaling
An easy and fairly safe way to close all your open applications, and start again with a fresh desktop