vertex snapping

Help !!! : hi , please help me a have a problem in Vertex Snapping ; i follow the instructions in every tuto talk about vertex snapping but i can’t do it when i press V and i select the object for move it the object stills in its position it dosn’t move my version of Unity is 4.3.4

Are you sure the transform tool is selected?
Are you selecting the object before pressing the V key?