last night i was using the laptop, then i pick it up, tiny little knock, then it shut itself down, and will not power up again.
I don't know what to do, been google around and still no luck... wonder if anyone had similar experience
I assume that you have tried removing the battery and tried to start it just on AC power? Have you also just tried starting it on the battery? If none of those options worked and based upon the knock noise, it sounds like something may have blown in it. If it is still under warranty, I'd get in touch with Dell to see what they have to say.