Yellow Box on screen

On the left bottom corner of my screen I have what looks like a yellow post-it and I cannot seem to get rid of it.

What it is and how do I get rid of it?

I got it by accidently mashing some keys on my keyboard, I must have activated a program by accident.

There is a close button on it, it will drop to the sys tray, you can right click and quit it too.

Sounds like a plasma widget. Try right-click on desktop, unlock widgets, and then see what happens when you hover the mouse over the post-it-like-object. If it is a plasma widget there should be some sort of window bar that sticks out.

Thank you, both of you.

Unlocking the widget allowed me to get rid of it following the rest of the directions.