2001 sunfire ignition problem please help!

Okay so yesterday my mom drove my car and she called me saying my ignition was just spinning around and it wouldnt start. Well naturally i assumed it was the lock cylinder because its been able to start without a key for a while haha. Well i bought the cylinder (i dont know how to put it in but a friend said he would do it) and i popped off the plastic covers on the steering wheel and the plastic part of the cylinder, you know the part on the outside where you put the key in, flew off and now i can put the key in and i can turn it to position 1 and 2 but when i try to start it it turns but nothing happens. There is a buzzing/grinding noise when i turn to start it but it stops after 3 seconds Does anyone know what the problem is? Is it still the lock cylinder like i thought?