Do you see the screen flash with something on it, then go dark? (it should be something relevant to what brand and model you have) If you see that, that means it is coming on but not booting. If nothing at all happens, then it could be your power supply (the one that goes from the wall to the back of your computer).
It's possible there was a power surge in the electrical wiring of your house and your computer is fried somewhere (hard to guess where). It's also possible that malware is keeping your computer from starting. It could be that the accidental, hard shutdown has corrupted critical system files and now the system will not boot.
It's really hard to nail something down as the issue over an internet forum. I can come up with scenarios all day as to why it's not booting, but I don't really how to get you to test things and diagnose it over this forum. Somebody else may be able to, but I'm not qualified for something like this (I can handle computers that are booted, but ones that are dead are a little more trouble). I could fiddle with it if I had my hands on it and possibly fix it, but trying to explain what to do to somebody else over a forum is near impossible. Wait a few days and another person might come by that has better experience with stuff like this.
If I was stuck in your scenario with a non-booting computer, I would take it to the Geek Squad at Best Buy and let them sort it out. I'd rather pay the money and have them fix it in the matter of an hour, rather than spend a week pulling my hair out trying to fix it myself.
Best of luck to you.