Left laptop for a while downloading torrents, suddenly it turns off and wont boot,

LED flashing only? I've recently had my laptop fan cleaned due do the same problem written above by overheating, but now the same is happening except that the laptop wasn't doing anything other than downloading torrents? It's been working fine for 4 days since the cleaning, untilnow. Heck, my laptop wasn't even warm when it turned off! I hope someone can identify the problem, or help me sort it out. Thanks for your efforts..