first decide what you will be using the computer for, then pick out a motherboard with a chipset that fits what you want to do. You probally are not worried about speed because you are a beginner to computers so dont worry about that. After you get the motherboard with the chip set you want you have to pick out a processor, and the most common one beginners use are pentiums. After that you just have to get ram, power supply, video card (you wont have worry about the video card as because you are a beginner) a hard drive 100 gig will be enough, get a cd rom and a floppy drive and a case and assemble it. There are other options but just for a first computer thats what you need. Get a copy of windows XP and install it