Pull the HDD out, try turning it on. If nothing happens still, then it's either a problem with your mobo or a problem with your battery/charger. Even without a HDD, it'd still at least boot up either straight to the BIOS or give you a "no media detected" error.
Generally speaking, if absolutely nothing happens when you push the power button, the laptop either has no power, or the motherboard is damaged in such a way that it can't boot. Even if RAM was bad it would still at least boot up to a certain point.
I would suggest doing the following:
1) Remove the battery, and try turning it on with just the charger plugged in. If it works, your battery is borked.
2) Remove the charger, try turning it on with just the battery. If it works, your charger is borked.
3) If multiple RAM modules are installed, pull one and see if it boots. If not, replace the one you pulled and pull the other, see if it boots. If it does, one of the RAM sticks is possibly bad, or the RAM slot itself is shorting something (which is unlikely)
3.5) If only one stick of RAM, pull it and see if you get a beep code. If you do, reseat the RAM into the other slot and see if it turns on. If not, then likely a bad RAM stick/bad RAM slot.
That would rule out just about everything beyond the motherboard, or both the battery and charger being bad (which is unlikely both are dead).