Pc wont turn on after power outage.But the lights are on but the monitor, keyboard and mouse doesnt work. I need help asap!!

You probably can't if it is true that the motherboard was fried. I'm sorry but it may require you to buy another component or two, depending on what received damage. So sorry if that's the case :(

More specifically you might need a new motherboard. And but some surge protectors, too!