If a person, or spaceship etc, moves at light speed; will he/it crash when something else blocks their way?

It sound like a scene from Star Trek. When Enterprise goes into warp speed, it simply moves at light speed and vanishes. It looks as thought the whole spaceship has undergone matter transformation. Theoretically, light itself can be stopped by an opaque object. Therefore, any object that can theoritically travel at light speed will crash with an atomic explosion when something blocks its path. This is because the object become infinitely mive in accordance to Einstein principle or relativity.