Remove Side Menus on certain pages in Drupal 7
Did you added the menu on the left side menu bar using blocks or printing directly from the template?

On the first case you can hide the blocks on specific pages in many ways. The easiest is to configure the visibility from the blocks configuration (Administration > structure > blocks). On every block settings you can specify in which pages hide or show the block.

If you're printing the menus from the template you've to use some php in order to select when print them, like "if current page is x, then print" or something similar.

:-)