My monitor is upside down and I don't know how to fix it

Press ctrl + alt then press the up arrow

If that doesn't work, I advise Right-Clicking your desktop.
Then, look for a tab that says "Graphics" or "Display Properties" etc...
Rotation is usually in there. If you are still having issues, check for viruses that affect graphics drivers, or contact your Graphics Card Vendor for assistance.
Usually with Laptops, the graphics card enables 4 different views. 90º, 180º, 270º etc...

Hope that helps.
- ANETGames

Unplug it, turn it the right way up, plug it back in.