Before replacing the belt, unplug the GE Profile dryer or turn off the electricity at the circuit breaker. You must turn off the electricity before you service your machine; even gas dryers use electricity for some components, and you risk major electric shock or even death if you don't turn off the electricity. You don't have to make any other special preparations, although you should gather your tools before beginning.
You must open the dryer to the point where you can reach the dryer drum to change the belt. Open the dryer door and unscrew the screws under the top lip of the door. Remove the top of the dryer and unscrew the front panel so you can remove it. Don't touch or damage the door-control wires when you do this. There should be a screw on each side of the dryer, about 6 inches off the floor. Remove this screw and push the sides of the dryer apart to get to the drum.
Pull the drum toward you to access the belt. The belt will be on the backside of the drum, near the motor pulley. Reach around the drum and remove the old belt from the motor pulley. Pull the drum up slightly and remove it from the GE Profile dryer. Remove the old belt from the dryer.
Put the new belt on the dryer. Make sure the ribs of the belt face inward, toward the drum, and that the slack part of the belt is nearest to the motor. Replace the drum, the panel and the top of the dryer, replacing all the screws as you go. Pull the dryer out from the wall and remove the back panel by unscrewing it. Reach inside the dryer and gently grab the belt. Loop the belt around the motor pulley and turn the drum by hand to tighten the belt. Replace the back panel and plug the machine back in.