Building a PC is a protracted, multistep process. First you must pick a platform and choose a case to best suit your needs. Then you have to do some research and acquire the individual components. Finally, once you've chosen all of the components, you can begin the actual assembly. See the first installment in this two-part series, "PC Building Best Practices: Hardware," for our complete guide.
The build doesn’t end once you've physically assembled the system, however. After putting together all of the components, you must install software on the system before it’ll do a darn thing. Unfortunately, many inexperienced builders simply slap the parts in, burn through an OS installation, and call it a day. Although that may get a PC up and running quickly, several additional steps are necessary to ensure that the computer runs reliably and at peak performance.
System builders should confirm that their components are outfitted with the latest correct firmware or BIOS revisions where applicable, as well as the best drivers. Builders should fully patch and update the operating system, too, and they should complete any tweaks needed to wring additional performance from select components.
Let's get started, shall we?

BIOS and Firmware Updates

Some users will argue that it’s not necessary to update a component’s BIOS/UEFI or firmware unless it is to address a specific problem, while others think that keeping every component up-to-date in an attempt to prevent future headaches is a good idea. I agree with the latter viewpoint, as updated firmware commonly addresses compatibility and performance issues, and occasionally adds new features.

When you're assembling a new system, check the component manufacturers' websites for new BIOS/UEFI files or firmware releases for motherboards, solid-state drives, optical drives, add-in-RAID cards, and (to a much lesser extent) graphics cards. Many computer components purchased at retail or online have been sitting on a shelf for weeks, or maybe even months. During that time, many manufacturers continue to refine and improve the firmware on their components. To benefit from those refinements, you must install the newest firmware version.
Motherboard manufacturers frequently update their products to address incompatibilities, enhance overclocking capabilities, and add support for new processors and memory, among many other things. Most modern motherboards have built-in tools to flash new and updated BIOS/UEFI files. You can download the files from the motherboard manufacturer’s website, copy them to a USB flash drive, and flash them using the built-in tools. If you have an older motherboard that does not offer an integrated flash utility, however, typically you will have to flash the BIOS using a bootable drive that boots to DOS or from within Windows.
Firmware updates for solid-state drives and optical drives vary from manufacturer to manufacturer. Some provide stand-alone executable files that you need to run in Windows, while others run from bootable drives in DOS mode. For optical drives, firmware updates commonly address compatibility issues with new media, and often improve write performance. In contrast, because solid-state drives are a relatively new technology, SSD firmware updates can be much more substantial. A new SSD firmware can occasionally change the entire performance profile of the drive--usually for the better. Many SSD firmware updates, however, are destructive and will wipe the contents of the drive, so check for an update before installing anything on the drive.
Updates for add-in RAID cards and graphics cards are much less common, relatively speaking, but before you put together a system you should check the manufacturer’s website for updates anyway. Firmware updates for RAID cards can improve performance or solve corruption issues, while updates for graphics cards commonly address motherboard incompatibilities or squash bugs. Such updates may have to run from DOS or within Windows; the process varies from manufacturer to manufacturer.

Operating System Installation

Although you have a myriad of operating system choices, for this article I’m assuming that you’re a Windows user. That said, a proper installation and update procedure is important for any OS.

Installing an operating system doesn’t end when you’ve finished the initial setup and the system has booted to the desktop for the first time. Unfortunately, this is the point when many users start to install apps and pollute the system with junk from around the Web. Instead, immediately after installing Windows, connect to the Web (which may require installing network-card or Wi-Fi drivers first) and run Windows Update. And after completing the first round of updates, keep running Windows Update over and over until no more patches are available. Many security holes in Windows and its included applications need patching after a fresh installation, and it’s best to plug those holes right away to minimize your risk of infection. Some updates also fix compatibility problems with third-party applications or add features to the OS. Pay special attention to the list of updates being installed, however. Windows Update will also offer to install drivers for some components. If you’ve already downloaded drivers for your components from the manufacturer’s site, you have no need to install what are likely much older drivers from Windows Update.