When you're upgrading to a new PC, you might wonder what to do with your old hardware. You could sell it or keep it as an emergency backup machine, but you could also put it to more creative uses.

Before you dispose of your PC and buy a new one, consider whether you can improve it (by upgrading parts rather than the whole machine) or repurpose it. Here, we'll share several DIY projects to repurpose and reuse old PC parts. Since no part can live forever, we've also thrown in some ways to trade in your old hardware, turn it into cash, or recycle it responsibly.

1. Media Center

One of the most useful things you can do with an old PC is to move it into your living room and repurpose it as a media center. You can watch movies and TV, listen to music, and play games by installing and setting up Kodi or similar software on your machine.

Kodi is designed to be used with a remote control, so you can link up your old computer to your TV and browse from the comfort of your couch.

A nice benefit is that media center software is lightweight and doesn't require a lot of system resources, so you can use it even on very old hardware. Alternatively, you could just install a free media player for Windows.

2. Run a Geek Projector

Got that media center running, but still need an affordable way to turn it into a home theater? Find an old TFT screen, even one with a broken backlight, and use it to build your own geeky projector. You will also need a working overhead projector and that media center mentioned above to run the movies or whatever else you want to watch.

3. Build a Home Server

If you live with housemates or family, it's great to be able to share your music, videos, and photos with them. Even if you live on your own, you can benefit from having a place to store all your media.

This is where a home server comes in. You can use your old PC to host your media and other files and access them whenever you need. This is handy if you only have a limited amount of hard drive space on your new PC.

You can also give access to the home servers to other users on your network, allowing you to share your files with them.

4. Set Up a Web Server

Alternatively, what if you want to host files on the internet? If you have your own website, you can host your site yourself from home instead of paying for hosting.

You can set up your old PC as a Linux web server relatively easily. Once the web server is set up, you can host your own and your friends' websites.

You can also set up the web server for FTP use if you want to share files over the internet but not create a specific website. When you or your friends want to access the FTP server, you can use Windows Explorer as an FTP client.

5. Run a Games Server

If you're a gamer, a really neat feature of the Steam client is the Steam Stream option. This allows you to install games on one machine and then stream these games to other devices on your network.

This means you can host your games on your old PC and play them from a media center or other device in your living room. Or you can pick up a small and fairly cheap device called a Steam Link which plugs into your TV or monitor and streams the content from your server.

With a Steam Link, you can even play Steam games on Android, which is great for phone and tablet users.

6. Create a PC Testing Rig

If you build PCs often, or if you frequently benchmark components, then a test rig is extremely useful to have on hand.

It's easiest to use if you have an open test bench, so you can swap parts in and out quickly. And you can buy a solid, well-made test bench if you're a serious builder. But you can also throw together your own test bench from metals, bits of wood, or whatever else you have on hand if you want a cheap option.

Once you have a bench, you can transfer parts from your old PC onto it, safe in the knowledge that all the parts are good and working. This will let you troubleshoot new components easily.

7. Build a Digital Photo Frame

If you replaced a mostly functional laptop with a nice screen, you could turn it into a digital photo frame. If the Wi-Fi is still working, you could even make it display your Twitter feed or your Instagram photos.

Still using Flickr? Slickr turns your Flickr photos into screensavers, or you can use it for setting up your DIY digital photo frame, as they did over at Popular Science.

8. Build a Frame PC

A PC isn't just a functional object: it can be art as well. This unusual project puts your PC into a picture frame which you can hang on your wall.

Using Wi-Fi sync functions, you can modify your framed PC and send and receive files. And you can power the PC with a single power cord from the bottom of the frame.

You will need to do some modifications to your components and to your frame to allow for issues like air flow, so this is a project suited to the handy and experienced system builder.

9. Install a Wall-Mounted PC

If you like the idea of a frame PC, but you want something a little easier to put together, try a wall-mounted PC. This example uses the motherboard and hard drive of an old computer, but is designed to be wall-mountable.

This project does require some tools for cutting the frame into shape, but it's fairly simple. If you don't have the right tools, you could either get the parts cut by a local workshop or, if you buy the material there anyway, your local hardware store.

Note that you don't even have to use wood for the base; it's kind of expensive right now. You can upcycle material left over from previous projects, maybe a sheet of plywood or particle board, or you might figure out a design that works with old picture frames.

When you have your base, transfer the parts from your old PC to its new case, then hang it on the wall. This design uses Plexiglas to close the wall-mounted case, but you could also leave it exposed, which would be better for airflow, although you'd need to be aware of dust. Either way, it's a fun way to turn your PC into an art piece.

10. Set Up a Home Security System

If you have a simple webcam, you can connect it to your old PC to make your own home security system. Using software that detects motion and triggers an alert, you can get a notification or set off an alarm if there is unexpected movement in your home.

Follow CooleFriend's tutorial to turn your computer into a video surveillance system.

11. Set Up an External Firewall or Router

Separating your firewall from the PC you are using, and running it on a standalone computer that sits between the internet and your actual operating system, is a powerful way to protect your data. With Linux as the firewall computer's operating system, it's almost perfect.

Lockup has a guide on how to turn your old PC into a NAT firewall router. At Associated Content, you will find an article that explains how to use free software to set up a first class firewall. And finally, Instructables has a guide on how to build your own gateway firewall.

12. Make a Desk PC

If you're feeling really ambitious, you can build your old PC components into a custom desk. You fit components into a compartment below the desk level and then put glass or clear plastic on top. This way you can see your components beneath the surface of your desk. It looks absolutely amazing, but be warned: it's not an easy project!

You'll need to design and build your own desk with a compartment big enough to fit all your components. And before you begin, you should know that getting the layout right and performing maintenance on a desk PC is a big hassle. But if you have the time and the patience, your own custom desk PC is an incredible and unique project.

13. Build a Mineral Oil-Cooled PC

Another impractical but stunning PC project is to build a mineral oil-cooled PC. Because mineral oil is not electrically conductive, you can submerge many components into it without damaging them. In fact, it will increase their lifespan by lubricating them. And you can get terrific cooling performance as the oil dissipates the heat.

This is another case in which maintenance is a real pain, though, and trying to reuse parts which have been in mineral oil requires an enormous amount of cleaning. So it's better as a show PC rather than being your everyday workhorse.

One thing to remember is that when using old parts, you'll need to clean them very thoroughly before submerging them in oil. Or else any dust or grime left on them will float around in the oil, and that's not good.

14. Create an External Hard Drive

You don't have to reuse your entire computer. Many of the parts make great DIY projects all by themselves. So if parts of your PC are broken beyond repair, salvage what you can and put it to good use.

For example, you can dismount and transform the hard drive into an external and portable drive for your new computer. You'll have to invest in a USB caddy, which you'll find on eBay, Amazon, or your local hardware dealer. Be sure to get the right size caddy and cable for your hard drive. For a laptop hard drive, you'll need a 2.5" IDE or SATA caddy. For a regular hard drive, generally a 3.5" IDE or SATA caddy is in order.

15. Make Money

Exhausted all your creative options or just need a bit of cash to fund your next DIY project? You could dismantle your PC and sell working parts on a second-hand selling platform like eBay. This also works if you just want to upgrade select PC parts; in that case, also read about the best sites to buy computer parts.

The hard drive or SSD, RAM, power supply, motherboard, graphics card, audio card, and even an intact case should make you at least a little bit if money. It's not an incredibly creative use of your hardware, but it's better than letting it rot in your storage or, worse, turning it into electronic waste.

16. Make Someone Happy

You can make money with your old hardware by selling it whole or in parts on eBay. Or you could make someone happy by donating it:

  • Computers with Causes is a great place to start if you're in the US, and your donation will even be tax-deductible.
  • InterConnection refurbishes donated computers and distributes them to people in need, such as rural schools in Chile or disaster-stricken communities in Haiti or Pakistan.
  • Freecycle.org has local groups all over the US and other parts of the world. If you'd prefer for someone to pick up your donation, this is a great option.
  • If you live in a city, you might find a Buy Nothing Project group for your neighborhood. Most of the groups are on Facebook, but they're currently moving off of Facebook onto the Buy Nothing Project app.

Before you donate your computer, be sure to completely wipe the hard drive to protect your personal data.

17. Turn Your PC Into a Science Project

If you're not ready to part with your computer just yet, maybe you can think of some neat experiments for it. Here are some ideas:

  • Donate its CPU time to science: Projects like SETI@home (currently in hibernation) popularized sharing CPU resources. Today, only a few remain, including Einstein@Home, Folding@home, and Rosetta@home. They all use your computer's CPU power for large-scale science projects. The computer could sit anywhere in your house where it gets electricity and internet, and would require a monitor only occasionally. You can find more projects like the ones mentioned above at Science United.
  • Use it as a sandbox: If you can't turn it into a web server, you can use it as your torture machine. Abuse it anyway you want, install anything and everything. If you ever saw some free app you like the look of, but aren't sure whether it's a virus or not, you now have a sandbox to test it in. This is a real sandbox, not those fancy software sandbox techniques that are so common nowadays. You can do all your damage here; just make sure to keep a Windows install disc handy.
  • Try Linux: Linux is a science, right? If you're a Windows user, that old spare computer could serve as your Linux study machine. And you may just be surprised by how smoothly Linux runs on your old machine. Be sure to take a peek at our guide on how to get started using Linux before you dive in.

18. Recycle Your Old PC

Eventually, all hardware dies. If you can't see a good way to reuse your PC or parts of it, it's time to dispose of it. But don't just toss old hardware in the trash! The metals and plastics in your PC are valuable and can be recycled at a recycling plant close to you. Old lithium batteries need to be disposed of properly, as they can cause fires and pollution (SoundGuys).

Here's how you can responsibly dispose of your electronic waste:

  • Check for brand-specific recycling programs: Companies like Apple and Microsoft offer take-back or trade-in programs for their own hardware. If you bought your PC at BestBuy, you might be able to trade it in there.
  • Check for local recycling facilities: Earth911 is a great place for readers in the US, while Recycle My Electronics will set you up if you're in Canada. Everyone else, please request a location-specific recommendation from Google.

Don't Throw Out Your Old PC Parts, Put Them to Use!

Just because your components are outdated doesn't mean they're not useful anymore. Working but old hardware is ideal for using in experimental and unusual projects. Or the hardware can be repurposed in a more practical way and turned into a server.