Mmmkay, alot of people are completely missing what ZombieDroid is trying to talk about by not reading the thread ect ect, albeit, some people aren't, and are doing a great job.
Hollywood zombies simply cannot exist, due to the fact that autonomous movement means life, and life cannot mean death. So if the 'zombie' is moving and attacking, it isn't a zombie. The only way to justify there being hollywood zombies is to use magic or some otherworldly force that does not exist.
Omitting every other type of zombie besides the shambling brain eating kind, you just can't have them. You need a brain to function, period. Anything else is either alive, robot, or not a zombie. Motor function depends on electric signals and unless you put a computer in there, effectively making it a robot, not a zombie, then its not a zombie.
You want proof of the impossibility of hollywood zombies? Just make a diagram of the body and how it works together to produce life. Then draw a shell of a body, representing the parts that work after death, Problem solved. Or, just write, "Dead is not Alive"