Accidental Knock Causes Computer to Freeze

So I accidentally knocked my computer (lightly, mind you) while watching a YouTube video and suddenly everything stopped responding.
The symptoms included:
Speakers creating repeated single sound from frame of YouTube video
No Mouse Response
No Keyboard Response
Power Remained On
Nothing Disconnected

Upon restarting the computer, everything seems fine, although I'm worried that something might have become damaged or perhaps this problem could occur again as, like I've said, the knock was very light.