Why are there random colored pixels flashing / staying on my desktop?

When I have my desktop turned on, a bunch of different colored pixels appear on my screen. I know it is not my monitor because I tried plugging my pc into another monitor, the same pixels show up randomly (in different places). When I am playing downloaded and installed games, I see a significantly larger amount of those pixels. I would send a picture but I don’t very know how to. Also, I tried updating my driver, and uninstalling and reinstalling, but nothing changed.