ok, ignor what he said -.-
let me sum this all up to make you feel comfortable.
Building computers are like puzzles.. they seem hard, but a few good hours and you had no idea what you were afraid of. there are guides ALL over the internet and we are also here for you.
now heres what you will need for a decent computer build
#1. A case. ever try building one without a case?
#2. Motherboard. This is the thing EVERYTHING hooks up to.
#3. Processor or CPU. Central Processing Unit. This is basically the brain of your computer. without it your screwed.
#4. Memory, or RAM, Random Accessed Memory. Trust me, you want at least Two Gigabytes of this...
#5. a PSU, or Power Supply Unit. this is what turns on your computer... a lot of cases come with PSU's but, if you want a good one... buy it separate.
#5. HDD. Hard Disk Drive. This is your storage. depending on what you do, is how much you need. i have a computer with 2 Terabytes. and a laptop with 50 Gigabytes in it. but then again i use my laptop ONLY for work....
#6. (optional) GPU, Graphics Processing Unit (i think). This is also known as... Video card, or Graphics card. If you are a gamer, you most likely need a GPU.
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Now for the rest that you may allready have.
Monitor.
Mouse.
Keyboard.
and a plug =)
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Any more questions im happy, and im sure the rest of this community is happy, to answer.