If the seller sent you a counteroffer and you accepted it as is (did not renogiate or re-counter), then yes, your offer should be be binding and forms a contract.The fact that you did not yet sign the contract should not matter in this case, since you have something in writing--the emails--showing acceptance; the emails plus the contract, it could be argued, together constitute an accepted written contract of sale. Also, the important thing for this purpose is that the *seller* signed the contract, since if the party you are attempting to enforce a contract against signed it and there was, from the evidence, clear indicia of a mutual agreement, that again can form an enforceable contract.That said, if the other offer is sufficiently better than yours, the other party may be willing to break its contract and pay damages to you for such breach. If you are serious about this house and want to try to force the seller to go through with the transaction (if the seller ends up taking the other offer), you should retain a real estate attorney to help you.