Try these two first:
Motor Coupling
If the washer won't spin or agitate the motor coupling might have failed. The motor coupling connects the motor to the washer transmission. It is designed to fail if the washer is overloaded in order to protect both the motor and transmission.
Drive Belt
If the washer won't spin or agitate, check the drive belt. If the belt is broken or if it isn't tight on the pulleys the washer won't spin or agitate properly. This may be what you're smelling.