Did you know that sleep walking has nothing to do with neurological problems or disorders? In fact, it's very common among adolescent kids, and not uncommon among adults.
When we sleep, we move through different levels, or cycles of sleep. There's deep sleep, or REM sleep, when we dream, and short periods in between when we wake up to roll over and shift around.
Sleep walking most often happens when there's some confusion between the cycles. Say you're coming out of REM sleep and heading toward wakefulness. Something happens to confuse your body into thinking it's time to get up while your mind is still asleep. As such, you start moving around while you're still technically asleep.
Sleep walkers have been known to get dressed, and respond to simple questions.
The best thing you can do to prevent sleep walking, is to get enough sleep. Exhaustion has been known to trigger sleep walking. Otherwise, therapeutic hypnosis has been known to help.