When I step away from my computer at school, I lock it using keyboard commands. On Monday, I pressed the wrong keys or something, because the screen did something weird, like it slid to the side or something.
My open Word documents were gone, so I had to open them again. Same thing for my browser windows. I got everything back to normal, but then that weird sliding-to-the-side thing kept happening when I opened files that I had already opened.
Yesterday, my computer was slow, and the sliding kept happening. It was like I had two screens or something. I went looking on the internet, and discovered it: you can have multiple desktops at once. I had two whole desktops full of open files and programs.
I closed down one of the desktops and things seemed to be working better.