Try it without the battery inserted, while plugged into the AC power. Sometimes a poorly seated or malfunctioning battery can be the cause. If it works, this doesnt mean your battery is bad.. Then try it with the battery installed to be certain. Also, you can try holding down the power button while the battery is out and it is unplugged from the AC power, then connect to AC and try again if it doesnt work the first time. This will discharge any stored charge from the PSU hopefully. Also try the reverse, with battery installed and no AC power to rule out bad power brick. If your battery has no charge, this will obviously not work though and if the power brick is broken you will be unable to charge that battery. If this doesnt work, leave the battery out and, if you have more than one stick of Ram, try removing a stick and then powering on to see if a bad stick of ram is causing a short.