How can you change fan belt if top bolt is stuck and rounded off?

If the top bolt of the fan belt is stuck and rounded off, first try using a rubber band or a specialized stripped bolt remover to gain extra grip. If that doesn't work, you can apply penetrating oil to loosen the bolt, then use a hammer to tap a smaller socket onto the rounded head to create a tighter fit. If all else fails, you may need to cut the bolt off with a Dremel tool or a similar cutting tool, taking care not to damage surrounding components. Once removed, replace the bolt and proceed with the fan belt installation.