Is it plugged in? LOL, just kidding. What do you mean when you say you 'dusted' it? What type of atmosphere has it been in? How did you dust it? Did it work immediately before your dusting?

Does it make any noise at all when you try to turn it on? A click perhaps? How about any indication (power) lights? Have you tried both the remote and the switch on the unit itself?

Make sure the outlet is working by trying some other device.

Other than the above, it sounds to me like your power supply has called it quits. Under no circumstance should you open the TV up. Unless you know exactly what you are doing, you can get seriously zapped.. and I mean seriously.