One of my medium-sized textbooks was standing up tall-ways next to my Macbook; to put it shortly, it tipped over when I looked away and the edge landed on the palm-rest area of my Macbook. The video conference I was in froze up and the system instantly went unresponsive. However, on a restart, everything seems fine. The hard drive checks out alright, no video artifacts or anything, battery seems fine, etc etc. Is there anything else that might have been damaged that I should check out? I can't think of any other moving parts as everything seems to be working. I don't understand why the system would have locked up (froze, totally unresponsive to anything) like that if nothing was bothered. Could it simply be the system locking up upon detecting a sudden impact/motion change to prevent damage?