Hi, PG! What version of Windows do you have? Go to Control Panel and in there you should find an icon for Display or Appearance. Go into that and check your display settings. You might be able to correct the screen from there. Other than that, I can only suggest doing a factory reinstall--in which you would lose whatever you've saved. If you have a restore point, you can go back to that point instead. Have you run your antivirus software?
I've missed your posting and hope you get your puter straightened out soon!
Have a good Thanksgiving!
"But that was yesterday, and I was a different person then."
Alice in Wonderland, Lewis Carroll