Thank You, Cleo, for your question. The seller does not have a legal obligation to respond to your offer. By not responding they are closing a door on negotiating a possible sale. If they are working with a Realtor, the Realtor will encourage them to respond. However, there is no way to force them to respond. You could send in another bid and personalize it, with a letter of intention, to see if that gets a response.
Best of luck in your negotiations!

The seller doesn't have to counter offer but more than likely he will. This is the part most people hate! The negotiations! But hopefully it will go well for you.

The seller has no obligation to counter. They may take whatever they want, as may a bank.

Do you have a buyer's agent working with you? They should be able to get a sense from the seller's agent what kind of response you will get. Personally I advise all of my sellers to counter, even if the buyer's original offer seems wayyyy too low. Quite often we manage to come to terms and if we don't we know we gave it our best shot.

Cleo,

The Buyer is under no obligation to counter your Offer and yes, they can they accept any price they that works for them. I am not familiar with your market; however, I know you area has been hit hard by this recession. If the Offer is within reason, any smart Seller would at least counter your Offer. If you submitted a low ball offer, you might have to make 100 Offers before you find 1 Seller that is desperate enough to take it.

Good luck!