Either you need a new battery or you need to let your laptop rest. it may have over heated

Try taking the battery out and then putting it back in then try plugging it into the wall, then try turning it back on if it does not turn on it could be overheated if not send it in to a computer specialist.

It sounds like your cable has died on you or isn't properly plugged in. Make sure everything is properly plugged in. Some laptop power supplies are separated into two cables and if one isn't properly plugged into the other it would not have charged the battery and it wont turn on. If you're still having problems PM me with a few more details on the symptoms you've got and I'll take a look. Good luck!

As a few people have said the best thing to do is this. Remove the battery, check the power cable is not damaged and is plugged in correctly. Then plug the laptop in (with the battery still out) and see if it turns on. If so great, we try with battery. If not then the power cable is broken or the input to the laptop is. So from here try the battery in and the power cable and see if it charges if so then it was the charger. If not then we need to look at the input on the laptop or the actual mobo being broken.

Try with only A/C power (wall). DIRECTLY into the wall, no extensions. What were you doing when this happened? Laptops don't just POOF! die. No black/blue screen? Nothing? Do you think you might have grabbed a virus? How old is this computer and when is the last time you have cleaned/vacumed it? Lastly get i.e. your Mother to keep moving around the wire and you spam the power button. If it turns on and off at least once, cable is broken. Also this has happened to me. I opened, and got into my computer. Put it back together and just said "OK, its gone." Then the battery was barely loose and I loled. CHECK THAT BATTERY!