Not all mountain systems were once volcanoes. Many of them are belts of rock that crumpled when two continental plates collided, forcing one plate to slide beneath another. The is an example of a mountain range that formed this way, among many, many others.

Himalayan Mountain

Explanation:

It is believed that mountains are as a result of aftermath of volcanoes but The Himalayan mountain  amongst others is an example of a mountain range  which is said to have been formed from the collision Eurasian   plates and the Indian plate which started out from the  crumpling and buckling of the Eurasian  continental plates over the Indian continental plates and acted upon by compression forces which caused the entire continental crust to fold upwards forming the mountain.

Another example is the The Appalachian Mountains.