You might also just select the gemoetry you want to smooth and export it as a maya ascii...this will get rid of all information in the scene that you don't need. Optimize scene and do...

check ur smooth option box...make sure you don't have the divisions up too high...my compy tends to start slowing down at about 3/4 levels (and maya definately crashes)

i find most of my crashes occur because i forget to delete history...make sure to do that before you smooth...and freeze transformations too. It's a good habit to get into. Saves you quite a few...