You can change nearly any desktop icon on both Mac and PC. To change desktop icons on a Mac, open the "Get Info" menu and paste in the picture you want to use. On a PC you'll need to make a .ICO file, ...

I hate to be the bearer of bad news, but that’s one messy desktop you’ve got. No, not your physical desk. I’m talking about the background of your computer. See for yourself: drag this browser window ...