Please help re: spell checking the wrong language!

I have a weird issue I hope someone can help me resolve. I am picking up where a previous learning developer left off, editing his Word and PowerPoint files and preparing to publish in Articulate Studio '09. I am using Vista and Office 2007.

Every so often I come across a section of text whose every word indicates a spelling error even though the text appears correct.

I have done everything I can think of to remedy this:

·         I right-clicked a “misspelled” word and selected Language > Set Language, and that’s when I noticed the language was set to Spanish (Puerto Rico). I changed it to English-US, but this did not have any effect.

·         I checked Word Options > Proofing to make sure the Dictionary language is set to English-US. It is.

·         I copied and pasted the contents of the document into a new blank document, but the problem traveled with the text.

·         I went into the Language Settings tool and removed the Spanish (Puerto Rico) item, and then rebooted the computer and took another look. That section of text still has a red squiggle under every word.

Has anyone ever encountered this issue? I’d be grateful if you could tell me how you fixed it, short of adding every “misspelled” word to the custom dictionary individually!

Thanks!