So you turn it on
1) does the green light come on at all
2) Does anything at all happen when you push the power button
If nothing at all happens then usually fuse 2 has blown it is surface mount 0603 style 500ma(check the game slot, if this shorts then the fuse blows) Both can be replaced if you are competent at soldering the fuse is mounted next to the game slot
If the green light comes on for 2 seconds then one of the screens flashes then everything goes off, then it is a fault either the connection, cable or screen that does not flash
If the green light stays on but no screen comes on then it is usually the wifi unit (plug in ) that has failed.
Of course if the power switch is loose then this has snapped off.
All parts are available but it is easier if you have another unit to fault find