So you finally bought a new computer and your old one sits in the corner and is collecting dust. That's too bad because there are a number of good uses for old computers.

Whether it's a desktop computer or a laptop, whether or not it's broken, and no matter how old it is, it can still be useful to you or someone else.

So if you still don't have any idea what to do with it, you might find some inspiration in this article.

1. Run a Geek Beamer

It's an unlikely scenario, but say you had an excess TFT screen, maybe with a broken backlight so it remains black, you could still use it to build your own geeky projector. You will need a working overhead projector and a computer or laptop to run the movies or whatever else you want to watch with it. Here's the how-to video:

Unfortunately, Tom's Hardware Guide took down the complete guide.

2. Create a Digital Photo Frame

If your old laptop screen is OK and if either the hard drive or CD/DVD drive are working, you can use it to build a cheap digital photo frame. With a working wireless connection you could even make it show your latest Flickr photos.

You'll find detailed instructions all over the net. Repair4Laptop.org provides an extensive list of instructions sorted by laptop models. Unfortunately, some links are outdated. If you have a spare G4 Powerbook, try this article at Instructables, and for the digital photo frame connecting to Flickr, Mike from PopSci used an old IBM ThinkPad T21 and Slickr, as described here. Shuttertalk has instructions using a LCD monitor and laptop.

3. Create an External Hard Drive

If parts of your laptop or desktop computer hardware are broken, you can salvage the working parts. So if the hard drive is still working, you can dismount it and transform it into an external and portable hard drive for your new computer. You'll have to invest in a USB caddy, which can be acquired cheaply through eBay, Amazon or your local hardware dealer. Be sure to get the right format and connector 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.

4. Make Money

You can dismantle your entire broken computer or laptop and sell the working parts on eBay. Hard drive, RAM, A/C adapters, motherboards, graphics and audio cards, and even an intact case will return some cash.

It's not a very unique use, but you may be able to save up some extra money to buy that cool tool you've been wanting to get.

To learn more about the inside of your computer, try Karl's Own PC building guide, a free MakeUseOf free guide. To succeed on eBay, apply my tips for private eBay sellers.

5. Make Someone Happy

The next best way to use your still working old computer is to make someone else happy!

You could offer the computer on your local FreeCycle.org group or ask friends, family, and people in your community whether anyone needs a computer for simple tasks. Alternatively, you could donate your laptop or computer through an official organization, such as Computers with Causes.

6. Donate CPU Time

If you would rather donate to something bigger, such as science, you could hook up the old computer to the internet, install a program such as SETI@home or Proteins@home, and run these programs all day and night.

The computer could sit in a dead corner of your house and would require a monitor only occasionally. You would invest as little as a bit of electricity and bandwidth.

Ryan has composed a great article about how 10 Ways To Donate Your CPU Time To Science.

7. Try Linux

If you're a Windows user, having an extra computer to play with is your prime chance to get familiar with Linux. And you may just be surprised by how smoothly Linux runs on your old machine. The reason is that Linux demands much less power.

Stefan has written a Linux guide for newbies, which will guide you through setting up Ubuntu and your first steps with it.

8. Use it as File or Print Server

Transform your old computer into a workhorse with only the essential software components, including Windows File and Printer sharing. Next, hook up all your external devices to it, such as an external hard drive or printer, and make them available to all other computers in the house.

9. 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.

10. Turn it into a Media Station

Load all your music and videos onto this computer, if necessary supply it with an external hard drive, set up your favorite media player, listen to Last.fm, install a TV tuner card and record movies, record music from radio stations, download MP3s, stream music throughout the house using wireless speakers etc.

There are many more options of how you can use an old computer for entertainment purposes, just be creative!

To help you set it all up, we have some material in store for you. Will wrote about the top free media players for Windows. Ryan covered the best sites to watch TV on your computer over the internet. Using a wireless connection, you could set up this additional "internet TV" in the kitchen or office. If you would like to record music, read my article about easy tool to record streaming music as MP3 files. And I'm sure you'll discover many more resources on MakeUseOf to help you find cool uses for your old PC.

If you're in the market for a new computer, our roundup of the best Windows PC laptops will help you make the right choice for maximum portability.

Image credits: ryas, dolar, svilen001, ilco