Computer power problem!?

a couple of days ago i just gotten my computer from the united states postal services and my computer is messing up now. the computer turns on and everything is pluged in but the monitor doesnt show anything but power saved mode. i toke off the computer wall and check inside to see if i can find a problem, everything was where it was when i sent it. when i turn on the computer i check the computer and mouse to see a light, the mouse does light up for a split second but goes away. the keyboard wont do anything to so i cant figure out what could be wrong, also the motherboard light does turn on to.

im going to take it to a computer place for them to check it but i think one of the computer parts might be broken. if anything got any guess please tell me.