Which is another good reason to just keep your hands off the mouse and keyboard. If you start blindly clicking away at buttons, or typing on the keyboard, the computer will execute whatever you have done in the order in which you did it. Next thing you know, you're really in a mess. Just hang on a few seconds until the computer catches up. If your PC doesn't have a HDD light on the panel, you might also listen for disk activity.
Most hard disks are far from being silent while their operating.
If you hear clicking noises coming from the box, it's more than likely the hard disk thrashing about. You can do a little test on your computer to see if it's going to respond. It's located at the top left of your keyboard. Many years ago I knew a guy who raised and trained horses on a small farm he owned. I remember his remarks concerning the intelligence of these animals which, according to him, was quite limited.