Putting an avocado in the microwave will not ripen it. There are several other methods that can be used to ripen an avocado.
The most effective way to ripen an avocado is to place it in a brown paper bag with fruits, such as bananas and apples. The fruit gives off gas which speeds up the ripening process. Other fruits that can be used are mangoes, pears and plums. If a brown paper bag is not on hand, a person can place the avocado in a bowl or plastic sack with fruit. This takes longer, but will help ripen it during the course of a few days.