Guide to Reusing PC Parts for Your Build


One of the greatest benefits of building your own setup is of course the ability to be smart about your component choices in order to get better performance for your money when compared to buying a typical pre-built system (that are oftentimes overpriced for gamers because most gamers don’t know any better and get wooed by clever marketing and a cool looking case).

But that’s not you, friend. As well as saving money by picking the best bang for your buck individual parts to plan the perfect parts-list, there are some other tips and tricks to save even more money on your build that you may want to be aware of and consider for yourself.

I’m talking about things like reusing any old computer parts and accessories that you or a friend/family member may have lying around, searching for lower-cost refurbished parts online, and buying what’s called OEM products for a lower price.

Don’t worry if all that sounds confusing as all will be explained in this guide on being a smarter hardware shopper, which isn’t for everyone but may very well contain some handy tips that you can successfully apply to your first build if you’re the thrifty type who gets a kick out of finding bargains. Let’s get this party started.


Reusing Old Parts & Peripherals for Your Build

Before picking your new parts, if you’re looking to save money anywhere that you can on your build you'll want to consider any components that you could possibly reuse.

If you’re building a new PC, chances are you may have an older desktop lying around that you could potentially scavenge for parts, although you’ve got to be careful when doing so as it could be more trouble than it’s worth.

When thinking of reusing a component, try and find the documentation for it online if you don’t already have it, as it’ll make your job easier when researching whether the specs are going to be compatible with your new system or not, and whether it has all the features that you need.

Also, remember to still keep safety precautions in mind when removing and uninstalling parts from an old system. See the module on preparing to build a PC later on for full safety tips. Ok, let’s look into which parts you may consider reusing, and things to keep in mind when doing so.


Which PC Parts Are Reusable for a New Build?

The most popular things to reuse are accessories like your keyboard, mouse, mousepad, monitor and headset.

Even if they use the older PS/2 connection format (green and blue circular port connections) and not USB which is now the common standard connection for accessories, you should be fine to still use them as modern motherboards still ship with PS/2 connections.

As for reusing hardware, some common parts you could consider reusing is the case, hard drive, optical drive, or power supply. You could even reuse Windows too in certain situations.

Parts like the CPU, graphics card, and RAM have less potential for reuse because they become quite outdated after a few years, so I would forget them unless you somehow have a fairly recent part that would still be compatible with your new parts and that would offer you the performance you want.


How to Reuse a Hard Drive

I probably wouldn’t use a really old hard drive that’s gone through a lot of constant use as your primary boot drive for your new build (as in, for the drive that stores your operating system), as it’s bringing along with it the increased chance that it could possibly fail at some point in the near future. Although to be fair hard drives can fail whether they’re many years old or fresh off the assembly line.

But if you want to use an old hard drive that’s not too old as your primary drive , then by all means go ahead. You’ll simply install the drive as normal into your build, and then you’ll need to wipe it clean, which is called “formatting” the drive.

You can do this on-screen just before you install your operating system onto the drive. You could also simply use your old hard drive as a secondary drive in your build for extra storage. If you’re porting over an old hard drive to use in your system and you’re keeping all the files on it, to be safe make sure to backup any important data first.

Plus, it would be a good idea to consider downloading the manufacturer’s utility tool from their website that tests the drive to see if its in a healthy working order and that it doesn’t have errors or bad sectors.


How to Reuse an Optical Drive

An optical drive such as a DVD/CD or Blu-Ray is another common component you could reuse for your build if you have one lying around and you want to include one in your new machine.

You’ll need to make sure your new PC case actually has a 5.25 inch drive bay that can house your old optical drive though, as not all modern cases come with these bays anymore due to the fact that optical drives are completely optional these days.

Plus, if your old optical drive uses an old IDE connection instead of the standard SATA connections used these days, you could always get an IDE to SATA adapter.


How to Reuse a Case

If you want to repurpose an old case that’s sturdy enough and looks good enough for your new setup to save some coin, go right ahead, but there are a few considerations to keep in mind and not all old cases will be suitable for reuse.

Firstly, make sure it will support the motherboard size you’re going with. So, if you have an ATX motherboard, make sure your case will fit an ATX motherboard as well as the motherboard back-plate, too.

If your motherboard is micro-ATX, your case will need to support this motherboard size instead.

Then consider whether the case has enough space to comfortably fit all of your other new parts (including potentially large parts such as CPU coolers and graphics cards), with ideally a little space to spare for potential upgrades too.

For example, if your motherboard barely fits in and touches the edges of your case, this is a hazard to avoid (the motherboard should sit a little higher than the case edge using standoff screws as explained in our PC parts installation steps).

Then there’s airflow to think about: make sure your old case has good enough airflow for your particular parts. If you’re cramming in high-end gaming components into a small old case with poor airflow options, it’s going to get real hot and dangerous in there (for your parts).

You’ll also want to thoroughly clean the old case and make sure there’s no dust buildup in there, as dust can quite easily hamper airflow and increase your new system’s temperature.

Lastly, think through whether the case has all the drive bays you need, as well as adequate front panel connections - if you want USB 3 or headphone ports on the front of your case, your old one might not have these (note that USB 2 would still be compatible with USB 3 accessories but won’t run at USB 3 speeds).


How to Reuse a Power Supply

Now things get a bit more complicated, and before explaining the important things to consider when reusing a power supply, it’s not something we generally recommend doing unless you know what you’re doing and thoroughly ensure the old unit is good enough for your needs.

If your power supply is quite a few years old and has been through a lot of hard use, it’s especially not recommended to reuse. How long are we talking here? Well, I’d say if it’s 4-5 years old or older, give it a miss as it may give you more trouble than the money you’ll save, and you might have to replace it soon anyway.

Newer power supplies are more efficient, which means lower power bills and longer-lasting and more reliable systems, as well as not having to worry about whether it’s going to fit and be of high enough quality to reliably power your new gaming build.

But if you want to reuse one, and it’s not too old, firstly consider whether your old unit has enough power (measure in watts) for your new components, including some extra wiggle room to be safe and to also take into account potential future upgrades.

For more on how much power you need for your new PC, see the upcoming section on choosing a power supply.

Secondly, you’ll want to factor in the overall quality and reliability of the unit, as it’s never a good idea to use a low or questionable-quality power supply in a gaming build, especially if you’re building a fairly powerful system that you want to last a long time.

To assess the quality of your old unit, you’re going to have to do your research on its specific model somehow to be sure it’s of good enough quality to reliably power your new beast.

Connections wise there shouldn’t be an issue, and if your power supply has Molex connectors - which has been replaced by SATA connectors - you can get a Molex to SATA adaptor.

What could definitely be a problem though is if you’re trying to reuse a power supply from a big-firm manufacturer like Dell or HP, as they sometimes use proprietary (as in, in-house) power supplies that won’t fit in a standard PC case. If that’s the case (pun intended), you’re out of luck my friend.


Can You Reuse Your Previous Windows?

If your old desktop was custom built though, either by you or perhaps a computer company, and the Windows on that machine is a “full” or “retail” licence, then yes - you can reuse that Windows on your new PC so long as you uninstall it from your old machine first as you’re only allowed to have Windows running on one machine at a time.

This still applies if you want to transfer Windows 10 that you previously freely upgraded from Windows 7, 8, or 8.1, as the full/retail license is kept intact after the free upgrade. You can transfer a full/retail license as many times as you need.

However, if your Windows is the OEM or DSP license though, which is typically what you’ll find on pre-built systems bought from large manufacturers like Dell and HP, then no you cannot transfer it to your new build because these versions of Windows are legally tied to the system/motherboard you first install it on.

So, as great as it would be to save the $100+ that a new Windows license costs, in most cases it’s not possible to do it when you’re building your first PC because it’s likely that your old desktop was not custom built (by you or someone else), and you’re going to have to fork out for a new copy because the old Windows you have is more than likely an OEM/DSP version.

If you’re moving a full/retail license of Windows 10, the license can no longer be active on your previous PC. There are two ways to first deactivate your Windows license before you can then legally install it on your new PC.

You can either format your hard drive, which will remove Windows, or you could uninstall your product key. To uninstall the key, in Windows 10 access the Command Prompt by pressing the Windows key + ‘X’ and then clicking on ‘Command Prompt’ or ‘Power Shell (Admin)’. Then enter ‘slmgr.vbs/upk’ and press enter.


About the Author

Julien "cyberjulz" is the founder of BGC and lover of all things gaming and technology. A computer programmer turned hardware enthusiast and web developer who's been keeping a close eye on the PC hardware industry since 2006, he's been an avid console and PC gamer ever since first stumbling across Warcraft 1 & Theme Park at age 7. His fav games of all time are OOT, Perfect Dark, GE007, SW Rogue Squadron, MGS2, DKC2, Starfox, WC3, HL1, HL2, C&C1, FIFA, & SWKOTOR.