Marko has ably tackled the They're/Their/There conundrum that seems to daily stump tens of millions of my proto-simian countrymen, so allow me to offer another free lesson or two:
1)"It's" means "It Is", as in "It's going to use a good dictionary intead of some idiotic spellchecker, just to make sure it isn't making an ass of itself." Conversely, "Its" is the third-person neuter possessive pronoun, as seen here: "Its LiveJournal became the laughingstock of the internet because it couldn't be bothered to learn to write at a third grade level."
2) Ditch Spellchecker, buy Webster's. "Reek" is what your skivvies do if you don't change them for three days running; "wreak" is what you do with havoc. If I read one more professionally edited and published novel where someone "reeks havoc", I'm going to
Pass this along. There are some fantastically literate people out there. Don't let Marko and I be left shouldering this burden alone. Help us...
...spread a bit of ridicule, I guess. It ain't like we're actually going to change anything, so we might as well get a chuckle from the cretins.