Allow the snow blower's engine to cool completely. Turn off the snow blower and remove the key. Remove the key from the ignition.
You will have to remove the control panel to disconnect the spark plug. This is solely for safety reasons because there's no way the snow blower can start without the spark plug connected. Unscrew the control panel with a Phillips screwdriver. The control panel housing is located near the top of the snow thrower. Disconnect the spark plug wire once you have removed the cover.
Locate the drive belt panel on the left side of the snow blower near the bottom. You will have to remove three screws, two locks-nuts, two cap screws and a washer in order to remove the panel. A wrench will be needed for the lock-nuts, but the sizes of the nuts can vary from year to year. This is where the belt is located. Twist the lock-nuts off with a wrench. Remove the panel to expose the drive belt.
Pull up the idler pulley to release tension so the belt is easy to remove. Pull it from the pulley, brake arm assembly and engine pulley reel, following the routing diagram, which will be drawn on a sticker inside the drive belt housing. Replace the new belt with the same routing pattern as the old one. If there's no sticker, draw a diagram for yourself prior to removing the old one. Replace the belt and reattach the drive belt cover with all it's hardware. Pull up on the idler pulley again to give yourself more room to route the new belt.