First of all, you need a computer case, motherboard, monitor, power supply, CPU, keyboard, mouse, cooling fan, graphic card, hard drive(s), DVD writer and memory. Tools you need are screws (comes with case), a flashlight and screwdrivers. It may seem expensive to buy all these, but you could just buy them when you think they are at their cheapest in a sale. When you get these items, make sure they come with everything needed to install it, or buy it if it doesn't. Once you have all these items, take off the sides and front panels. Put it away somewhere out of the way, as you won't be putting them back until about the time you finish building your computer.
Now that the panels are off, install your power supply. It's up the top at the back, and make sure the screws match up, as they are sometimes not at the corners. Next, screw in the ones which can have another screw attached on top of it (‘copper pillars', I believe they are called) in the correct places, as these will be the bottom half of a combined screw to fasten your motherboard in. Then, fasten your motherboard in. There will be an ATX plate supplied with your motherboard, so remove the appropriate plate from the back. Line up the motherboard with this ATX plate and the screws, and then screw the top part in.
Now install your CPU. The side the top have safety latches, so remove those before you install your CPU in the right way, then fasten it again. If the latches don't come down properly then you have installed it the wrong way, so don't force it down. Put thermal paste onto the fastened CPU (yes, it will look wrong, but do it!) then use your finger to spread it (not sure if you can come into direct contact). Remember to apply the correct amount (which is not a lot) onto it. Then, put thermal paste onto the bottom of your cooler. Secure it (always hard for me) then install the memory. Release the module by pressing it outwards then put your memory in (make sure they are in the right slot!).
Connect power to your motherboard (the white plug with 2 by something holes and the smaller black one next to it (if unsure check the booklet that comes with the motherboard). Connect power, reset, USB, audio and any other cables that need attaching (the motherboard booklet comes in handy). Almost there! (I hope). Remove the iron plate and plastic at the front (gently, now). Install the optical drives (booklets here) then connect power to them. Install the rails on the hard drive(s) (rails found with case). Install them then connect the power cable (I don't need to say the B word, so I?).
Graphics card time! Lay your case flat (it might already be like that). Align your graphics card with the appropriate slot, then screw it in and attach the power cable. If you need to attach any other interface cards then refer to the...
Connect power cable to the monitor and then the audio cables to the case (the back). Connect the DVI cable to case and then mouses or any other miscellaneous things. Attach power and network cables then you're done (hopefully) !
Let me know if I missed anything, and if you ask nicely, I'll try to make another guide instructing you on how to install your operation system etc. If you hated this, well, let me sulk in my c
