First, Make sure you connected the lid switch when you reassembled the machine. If the machine still agitates but does not spin and makes no noises that is the likely issue.

Next, With the washer turned on to the spin cycle you need to check for voltage between the blue and white wires at the motor. Do not try this if you are not familiar with using a volt meter, you can get electrocuted. If you do have 120 volts the motor is bad. If you do not have 120 volts check the blue and white wires at the timer, not having 120 volts means a bad timer. If there is voltage at the timer but not at the motor then there is a break in the wiring somewhere and is very hard to find.

All this is assuming the machine was able to fill with water and made no noises or humming when you tried to use the spin cycle. Double check the power coming into the machine as well in case a breaker was tripped.

If you have never used a volt meter before call a professional to avoid injury.