All outlets but one work in bedroom
Typical method of connecting outlets on the same circuit in a chain: 

 

This is the main reason outlets are made with four terminals instead of two. (I bet you thought it was so the outlet could be split between two circuits by removing the tabs.) 

Suppose you find that outlets 3 and 4 have stopped working, while 1 and 2 still have power. The failure is almost certainly at one of the terminals A, B, C, or D -- in other words, at the last live outlet in the chain or at the first dead one. 

This is a very common failure in home wiring when the builder has used the backstab terminals on the outlets instead of the screw terminals. The only excuse for ever using the backstab terminals is that your cheapass boss will fire you if you take the time to wire it right. 

Many professional electricians recommend wiring outlets like this: 



Those hookup wires from the terminal screws to the wire nuts are called "pigtails". They should be about 6" long. 

Wire nuts are certainly more reliable than backstabs. There is some disagreement over whether wire nuts are more reliable than screw terminals. The pigtails may be a bit of overkill but they allow removal of a problematic outlet without affecting the rest of the circuit.