Have you ever changed the screen resolution of your computer to where you have saved settings that your monitor cannot display? I have, several times. It's annoying at best to to have accidentally made a change and then not be able to see what you're doing.
Here are the steps to restore your display.
Please note that you have to be logged in.
If you need to blindly login to your account, I'll save those steps for a different post.
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Take an educated guess and
Click the Right Mouse button. - On your keyboard, press the
UP ARROW once, then press the ENTER key. - On your keyboard press the TAB
key four times. - On your keyboard, press the RIGHT ARROW
key four times. - On your keyboard press the TAB key once.
- Then press the
LEFT ARROW key four or five times - Then press the ENTER key.
The Monitor Setting dialog box will begin a countdown, "Reverting in n seconds".
Save your display settings.
And that should do it!