There are many "how to build your own computer" tutorials out there. My goal is to make this one the best and most comprehensive. Like the name says, here we attempt to build a complete desktop system, chiefly designed at high performance and geared towards gaming.
It's a lot cheaper and you can make sure you're getting good quality parts. There's no tech support to call - you're your own tech support. It has helped me learn a lot about computers. Also, in the past, I've ok experiences with some customize-it computer places (like Dell) but for the most part, computers tend to break. This is especially more likely if you're using cheap parts like many name brand computer companies do. This way, you can be assured you are getting quality parts.
I'll admit I was a little scared at first but now I work on and mantain several machines without flinching.
What you'll need
You will need mostly just money to purchase the parts. I HIGHLY recommend NewEgg, you might be able to find a cheaper deal by a buck or two somewhere else, but it's nice to place your entire order with newegg and have it get to you in three days or less. Plus, you save on shipping by ordering from one place. I have no affiliation with newegg, I just order with them all the time and have been extremely satisified. Need more convincing? read reviews at Reseller Ratings
Here are the basic parts for a computer, I'll go into more detail after the initial list.
6.CD/DVD Rom drive
The best components tend to vary over time, so the recommendations here might not be up to date. I recommend picking up an issue of Maximum PC magazine at a newsstand and flipping to the hardware reviews section. They should have a listed of high end and budget PC part recommendations. Another big influence for me is word-of-mouth and what other people say about a product - this is pretty evident on sites like newegg.com and amazon.com with user reviews.
Here are my personal recommendations:
1.Case - thermaltake makes AMAZING cases. They're expensive but you get what you pay for. If you are looking to build a cheap system, this is the easiest place to save money, cheaper cases may not look as nice, but they will hold up, and of all the components this is probably the easiest to replace, buying a $20 bargain basement case will let you spend more money on important components, then when you've saved enough money you can invest in the neon green case with 20 fans lights and the glowing skull emerging from the front, and just swap everything out to the new case. NOTE: if you are very concerned about cooling, you may not want to go too cheap
2.Motherboard (MoBo) - ASUS consistently makes great motherboards. I've never had a problem with them.
3.Processor - as we're building a PC, you have a choice of AMD or Intel. Recently Intel has been accused of some dubious business practices. I'm not going to get political here but it definitely made me look at AMD chips a little more. I have an Intel Pentium 4 in my main desktop right now but I put an AMD Athlon64 in my media center PC and its pretty sweet. It's hard to go wrong with either company, right now, I'd recommend an AMD Chip. Athlon64's are great and pretty cheap.
Perhaps the most important part, maybe, maybe not.
If you are doing this for the first time it's important to remember that as long as you take the right precautions, it's fairly difficult to fry an entire system, most importantly remember to STAY GROUNDED, this is of the utmost importance, an imperceptible amount of static is enough to fry just about any component, including that $300 video card you just bought, the easiest way to do this is to buy a grounding stap, these are extremely cheap and can be found at just about any place that sells components, it looks like a velcro bracelet attached to a plastic square (usually yellow) with a wire coming off of it, and an alligator clip attached to the end. to use it put it on your wrist and attach the clip to bare metal inside your case, this will discharge any static electricity and keep you from frying you components. Be sure that you are using one of these before you touch ANY of your components.
Outside of that as long as you are careful you should be okay, everything should have it's place in the machine, if a plug doesn't fit, DON'T force it, and make sure everything is compatible, especially your Motherboard, Ram, and Processor, many online stores will sell thes in packages, if you aren't sure those are a good option.
Test it with Windows! Then scrap Windows and install a good Linux distro like Ubuntu.
Sources and inspiration
I used MaximumPC some in building my first computer. They have a great list of currently recommended products at various budgets. Get a subscription or check our some of their stuff online maximumpc.com