Alt+F4 ?

Click the little "X" in the upper right???

what is mean?

I usually just throw my mouse down and walk away...

Simply drag your mouse pointer to the close icon 'X' or hold down you ALT key + F4

If you are asking if you can quit SolidWorks because it takes hours away from your time and it became a dangerously addictive hobby then I have bad news for you:
I don't think it's possible. I've tried other manufacturing CAD software and while SolidWorks remains maddeningly buggy sometimes, its interface and intuitiveness feels much better for me.
If you can't find the little X on the window 's top right then you may have entered the full screen display. Press F11 to get back to the normal layout.
I hope I understood your question!