For me, the hardest thing to do in building a computer is hooking up the computer case wiring. You are handling very small plugs and pins. Most of the time, you can't get to the plugs, because other wires and boards are in your way.
You might be asking why are you hooking up wires when you don't even have the power supply in the case yet. Well, there's a method to my madness. These wires are difficult to get in place, I like to put them in before any other wires get in the way to make the job a lot easier. So we'll start with the computer case wiring.
What are all those wires attached to the case? Most of you have seen the front lights on the computer when the disk drive is accessed. You've turned the front power switch on and off, and you've hit the reset button when your software hangs up. Well all that is controlled by the motherboard, the lights and switches on the front of the case are hooked to the motherboard through these wires. If you have any USB or Firewire ports on the front of the case they'll have to be hooked up also.
Let's get started. Get out your motherboard user's guide that came with your motherboard. Look for the diagram of the motherboard. What your looking for is where the ports are on the motherboard. Keep this page open as we proceed so you will know where plugs and cables are connected to the motherboard. Most User's Guides also show the connector pins in a diagrams so you know which pins are for what.
Look for a block of pins usually called "panel," or "front panel connector." The power on/off switch plug and the reset swith on/off plug usually are two-pin plugs. They should slide over their respective pins which should be labeled "PWRSW" and "RESET." You'll find a four pin plug which is your system warning speaker for beeps and warning signals when something is wrong, slide that over the four "SPKR" pins.
We have two lights on the front panel. One lets you know there is power to the system, the power on light, and the other is when the disk drive is accessed. Each are two pin plugs. The system power is usually labeled, "PLED," and the disk drive light is usually called, "IDE_LED." After you slide all these small pins over the posts on the motherboard, the hardest wiring is taken care of.
Most of the current cases, have a USB port on the front panel. These USB port(s) are different from the USB ports in the back of the computer. The ones on the back are already hooked up directly to the motherboard. So we're hooking up the front USB ports. Look for a connector on the motherboard labeled "USB58" or "USB76" or just plain, "USB." The plug from the front panel should be labeled, "USB." This is a 10-pin plug with one pin plugged up so there is only one way to install this on the motherboard.
The next cable is the audio cable, usually labeled "HD AUDIO," or "AUDIO." There may be another plug on this wire labeled, "AC97." Ignore this, and use the "HD Audio" plug if you have digital audio on your motherboard. If you don't the motherboard diagram will give you the AC97 port. The HD Audio plug is a 10-pin plug with a different pin blocked than the USB plug had. On the motherboard diagram is usually called "Front Panel Audio connector." This connector usually just looks like 9 pins sticking up in the air.
The last front panel cable you may or may not have. This is for your 1394 "Firewire" port, and this depends if you have a Firewire port on the front of the case or not. The plug is usually labeled "1394" and the motherboard diagram is usually called an "IEEE 1394a connector, or simply, "Firewire header."
That should be it for the computer case front panel cabling, except there's still a wire, or maybe two, floating in the case. These are for the case fans. Most motherboard have a couple of connectors for fans called "Fan header," or "Pwr Fan2", "Pwr Fan2," etc. These are three-pin connectors. Hook up your case fans.
You should now have all the loose wires in your case hooked up to the motherboard, congratulations.