Pasting into a new document will likely continue and/or compound your problems. You have Office 2007. That is the only version with the pizza button.

Follow the following steps, exactly, without skipping anything or guessing.

With your problem document open...

1. Press Ctrl-A to select all text in the body of your document.
2. Click on the Review Tab
3. Click on the Set Language Button (on the left side of the ribbon)
4. There is a checkbox for "Do Not Check Spelling or Grammar."
5. Check it until it is clear. Make sure that in doing this it is checked at least once. If there is any color or gray in the checkbox, it is not clear.
6. Click on OK.
7. Press F7 to check spelling.

What happens?