Toyota Sienna wont start after alarm went off?

I have a 1998 Toyota Sienna van. Recently the alarm went off on it and after we turned the alarm off the vehicle wont start nor even turn over it just make a humming sound its not the battery or the wiring. I've come to understand these cars have a theft lock out system where it does this. So how do I unlock it. I've tried the on-off key cycle and the locking and unlocking the car with the key but with no results please HELP this is my only car and I need it for work!!!