[Andy B]

Probably raise third. I don't know about the bet on fourth. Ordinarily, you might bet here even though you "know" the presumed raiser has Aces in an effort to get it heads-up. In this case, however, your hand is pretty dead, and I wouldn't be looking for reasons to get tied on here. I'd check and call one bet.

By fifth, I think your hand has become sufficiently dead that you can throw in the towel. Having called, you pick up an open-ender on sixth. You're looking at three spades, but the pot is kinda big so you should probably call and hope. Unless the other guy is a nut or something, I doubt that your hand is good often enough to make paying off the river worthwhile.