Macbook help please? kernel panic?

Kernel panic?
ummmm…..I need some advice….has anyone ever experiecned or came over a similar incident?
It happend once in the middle of december when I was playing “chopper” in which I downloaded from the apple website…all of a sudden there was a beep, and a small screen came up saying that I had to restart my computer!!! Then when I turned it off by pressing the power button…then on again….it said “mac os quitted unexpectedly” This happened twice that day….another when I tried to use parallels…. I ended up unistalling the game. THere was “peace” for a while everything worked perfectly…until today……while I left my computer on for some time and the screen saver was on….it happened again (except no “beep”)! Its not really an issue…cuz now everythings back to normal and works flawlessly. But, I’m wondering should I take the incidents more seriously? I ran an apple hardware test which said nothing was wrong with the computer.
anyone ever expereinced this?

p.s in early june I dropped my macbook…which broke the screen, the drive, and impaired the battery…all of which was covered under the warranty……… from that moment everything was good for like six months till it happend in decembeพ