* Overheating: The water pump won't function, causing the engine to overheat and potentially causing severe damage.
* Battery drain: The alternator won't charge the battery, leading to a dead battery and the engine stalling.
* Power steering failure: You'll lose power steering, making the car extremely difficult to steer, especially at low speeds.
* Air conditioning failure: No cool air. This is the least of your worries compared to the others.
In short, attempting to run the engine without the serpentine belt will likely cause significant and costly damage to your car. Do not attempt this.