Is 'ors' even a word?
Or's would be the punctuated word form of 'or is', or 'or us' perhaps.
Spell checkers are not punctuation checkers, after all. 'Ors' is not a proper word. Learn how to spell and punctuate, and your problems will be over.
http://www.merriam-webster.com is your friend.
Ors isn't a proper word? But isn't ors the proper way to write several ors?
As in "buts, ifs and ors"?
http://dictionary.reference.com/ Is my friend. Of course, it doesn't have buts, ifs and ors listed either, but the point still stands.