If you’ve never installed an OS before, it’s remarkably easy. If you have, I’d still suggest reading through this guide to make sure you’ve got it all down. Installing Windows on a custom machine can take a few extra steps than installing it on a pre-built machine. For this guide, we’re going to use Windows 7 as an example, but you can of course install Windows XP, Linux, or even Mac OS X, if you’re building a Hackintosh. Refer to our Getting Started with Linux series and easy Hackintosh guide if you’re using those OSes instead.
Step One: Edit your BIOS
When you first start up your computer, it’ll tell you to press a key to enter setup, usually DEL. This takes you to the setup of your Basic Input/Output System, or BIOS. Here, you can configure some of the lowest-level aspects of your new machine. You may not actually need to edit any of these settings, but it’s a good idea to go through, get acquainted with them, and make sure everything’s in good order before moving on.
Note that the BIOS will be a little bit different on different brands of motherboard, so your screen may not look exactly like the images here, but it should be close.
Find the SATA configuration option, and make sure its configured as AHCI. If you’re running Windows XP you’ll need to change this to IDE, otherwise AHCI is probably what you want to go with.
If you don’t see your hard drive listed, it may not be plugged in correctly or it may be dead. Turn your computer off and re-check the connection if necessary.
Step Two: Install Windows
Next, grab your Windows installation DVD (or flash drive, if that be the case) and pop it in. Start up your computer and it should automatically boot into the Windows installer. If you ever get a “Press any key to boot from CD” option, make sure to hit a key on your keyboard to continue.
From there, the rest is just a waiting game. Leave your computer alone to do its thing. It’ll copy all the necessary files to your disk and reboot a number of times in the process. You’ll know you’re done when you hear the familiar startup chime and boot into the default Windows 7 desktop.
Step Three: Install and update drivers
The last thing you need to do before you actually use your computer is install your drivers. If your Ethernet or Wi-Fi works out-of-the-box, Windows may find most or all of your drivers for you. If not, you’ll need to pop in the CD that came with your motherboard to install the Ethernet or Wi-Fi drivers you need to access the internet. Don’t install any other drivers from that CD just yet.
Once you’ve got the internet up and running, Windows will install drivers for you. It might not catch everything though, so you’ll have to install some manually. The CDs that came with your motherboard, video card, and other hardware are probably already out of date, so I don’t recommend using these to install those drivers.
If it says “Unknown Device” next to the driver-less device, try inserting the CD that came with your motherboard and seeing if there are any drivers that aren’t listed in the Device manager, and try installing those from the manufactuter’s web site. Eventually, you should be able to get everything installed.
Step Four: Install Windows Updates
This is also a good time to get some antivirus on your machine, as well as any other basic apps you want. Our Lifehacker Pack for Windows is a good place to start, and should get those “must have” apps installed in one fell swoop.
Congratulations! You’ve bought, built and set up a working computer from start to finish! Don’t be alarmed if you feel an overwhelming sense of pride; that’s normal. Enjoy your new custom-built machine, and be sure to come back tomorrow for more useful PC-building resources, as well as a handful of fun projects you can take on with your new computer.