Why my computer can't power up?

Hello everyone! I bought a Lenovo PC two years ago but hadn't used it since the last year. Then I found I even can't power it up a few days ago. Who can tell me the reason? Thank you!

Try to unmount some hardware and mount again. Sometimes i have troubles with my PC it doesnt load the OS. I'm unmounting video card

I agree, first thing is to unplug the hardwares that can be possibly unplug then plug them back, see to it that they are plugged correctly. If in the first place, your computer does not turn ON, the problem is in the power source. Check your Automatic Voltage Regulator which gives power to your CPU, if it seems working, try to check the Power supply located inside the CPU, maybe that is the problem.
_________________
My Animation Services