Exactly. That happened to me. IIRC back then the laptop shut down all of a sudden when I was in the middle of a game and won't turn back on! Even if I try to charge it... Which made me sure the battery wasn't the problem.
Well, this happened to me last year December too! I brought it to the Asus Service center and they told me the motherboard is dead. Luckily I still had warranty that time (now it's expired) so they replaced it for free :D