-Now with all that mess of installing RAM and a CPU it time to throw it in the case. (not literally) With motherboard aligned with your standoffs/motherboard spacers simply put the motherboard in. Now pay attention to the I/O shield which your ports go into. The I/O shield will tear easy so be careful. Now with motherboard in place go ahead and use the screws that came with case and screw in snug. Make sure there are no standoffs that are in wrong place and not being used. You do not want a standoff touching the circuitry on the motherboard. Take care also that none of the standoffs are on the wrong thread. If they are not screwed in on the right thread they may be at an angle to the motherboard and cause stress to the motherboard by not allowing it to sit flat.
-With the board in place we will go ahead and install the leads to the board along with the power connector. The leads I speak of are little wires that usually run from front of the case. They will be marked with speaker, power, and so on. Look at your motherboard manual to see which ones fit on the board. There is usually a block that allows you to plug them on to. If you put them on wrong don't freak. This will not ruin anything you may not have lights working on the computer an worse case scenario is the computer wont start. There is one led that is especially important and that is the power switch. If you are using a ATX or BTX board (AT is now defunct), there is a led that will plug onto two pins. This will actually work the power button on the front of computer. Plug in led connectors now.
-Now lets plug in the power connector from the PSU. This connector is a 20 pin connector or prongs. This connector only fits one way and you cant screw it up. Simply plug into motherboard using the motherboard manual as a guide. Newer CPU's also require a 12v connector plugged into the board. All PSU's have this connector, it has 4 pins in a square shape and it usually has 2 yellow and 2 black wires from it.
