Turn it off and on again
A lot of people might get frustrated, or maybe laugh a little, when someone tells them to turn their computer off and on again, but it really does help. Think of it like giving your computer a break, let it sit down for a second and catch its breath. When you turn it back on it starts over fresh and this can fix issues in the software running on your computer.
For those who know a bit about computer hardware this resets your computer's RAM making sure all programs start fresh.
BEFORE you do restart your computer however ALWAYS make sure to save anything you're working on. If you don't it will be gone forever.