An XLS file appeared magically on my desktop; the name is just a bunch of letters and numbers. I can't delete it, and I'm scared it's a virus or something nefarious. I tried using the terminal to delete it by typing in sudo rm filename, then typing in my password, but it says the file doesn't exist. When I view the dekstop in finder, the file doesn't show up. If I right click it and select "get info" nothing happens. What's the deal?