The desktop of my computer suddenly showed my icons and lettering in very large font, and everything is kind of fuzzy. I checked the to see if It was changed in appearance and themes and it is normal. Is this a virus.

Did the resolution of your desktop get changed?
On the desktop, right-click and select Properties (you were already there to check the themes). Click on the Settings tab, and on the left there is a Screen Resolution slider. If it has room to move to the right, try that.

Good Luck,
WallyH

Wallyhelps solution, right clicking properties on the desk top, then screen resolution, then moving slider all the way to the right, worked to fix giant font! Thank you so much! I have been struggling with this for three days! Thank you so much!