Motherboards come from computers. Older TVs, DVD players, radios, etc. all have circuit boards and none are as high grade as computer motherboards. Not everyone buys everything. Check the buyers section here and check with your local yard - find out who pays the most for what (make sure to include the price of shipping or driving).

Why use a hammer when there are perfectly good screws holding it in place? There are parts on circuit boards (not to mention the dust) that I really don't want to be breathing which is what would happen if you start swinging a hammer at it.