Linux has changed almost beyond recognition since version 1.0 in 1994 and Ubuntu is about as polished and professional as it gets. It's approaching the level of polish of Mac OS X, is faster and easier to install than Windows, includes a whole suite of apps and offers tens of thousands more, runs on cheap commodity hardware and costs nothing.

Nobody knows quite how many Ubuntu users there are - it's not sold or licensed, there's no registration process and it doesn't "phone home" and identify itself, so it's hard to tell. Its creators reckon around 12 million, but then, the number-two distro on Distrowatch, Fedora, claims about twice as many.

So with over a billion PCs in the world, why are only about 0.01 per cent using the best-known Linux desktop?

Two related pitfalls mean that most people who try it may well find that certain things don't work. Firstly, because Ubuntu is entirely built around free, open source software that is legal to use anywhere in the world, when first installed, it doesn't include some more or less indispensable but proprietary tools, such as Adobe's Flash player; nor is there support for ubiquitous formats such as MP3, Windows Media, Quicktime and so on.

Secondly, when people try to fix this, they attempt to use the methods they know from Windows or the Mac – go to a web page, download a program, run it to start the installer – and it doesn't work. Result: they give up and never come back.

How to avoid pitfall Number 1

Let go of your expectations and existing know-how. The Windows way to do things is often not the Linux way. Whenever you need to do a bit of admin or housekeeping, such as installing, removing or updating a program or device driver - don't try the way you know from Windows. Google it first. Usually you'll find simple instructions online and in a lot of cases it's quicker and easier on Ubuntu than the familiar Windows way.

The biggie is installing software.

Windows is just an OS, developed by one big team. The apps come separately, from third parties, so you have to go to them to get the software and future updates.

Linux is different: you get the OS, apps, drivers, media codecs and so on all from your distributor, who has assembled them all into a single, more-or-less integrated whole. So to add more software, and to get updates, you go to the distro-maintainer, not to the original source.

Because everything comes from one place, there's a single central package-management tool which you use for just about everything: installing, removing and upgrading the whole system. The main reason we're recommending Ubuntu is because its tool, APT, is the best, and stomps all over the rival RPM system used by Red Hat, Fedora, Mandriva, openSUSE and their relatives. It makes Control Panel | Add and Remove Programs look like a sharpened rock tied to a stick.

What you don't do is get program executables from unknown sources (such as downloading them from the web) and run them, like on Windows. Unix isn't trusting like that. So if you download a file off a website – even a special Linux program – you can't run it by double-clicking it, nor even from the command line. This is intentional, to keep you safe. From the Unix perspective of Ubuntu's creators, this is not a problem or a bug or a drawback, it's how it should be, so it's not going to go away or change.

Most of the time, you'll never see APT itself - it has various friendly graphical front ends, such as Synaptic (under System | Administration) and the dead-easy Ubuntu Software Centre. Either way, whenever you want to install or upgrade a program, APT fetches it for you, over the internet, from a local mirror of one of Ubuntu's continually-updated repositories, which contain the latest versions of well over 10,000 programs, including pretty much all the most popular open source applications. It's rare to have to download and install anything manually and it's best avoided until you're familiar with the system.

How to install

All right, enough preaching, so how do you do it, then?

Even if you never see it again and only use the graphical tools, for getting your shiny new Ubuntu box ready to actually use, you can't beat doing it the original way, from the command line.

But first, a word about installation. It's very straightforward – it's pretty much a case of putting in the CD, booting up, and clicking the "Install" button. Before you begin, connect your PC to the internet, using a cable, not wireless. Wireless LANs are one of the worst remaining driver problems for Linux, but sorting this out is vastly easier if you're already online. In fact, a lot of initial driver niggles will go away if you just update and reboot. If you've already created your partitions as described in part two, choose a manual installation and tell it which ones to use for "root" (the system disk), "/home" (your data) and swap. Just use the default disk format, ext4.

Once it's done, reboot, remove the CD and watch Ubuntu come to life.

So long as it can reach the internet, a couple of minutes after you boot an Ubuntu PC for the first time, it will go online and check for updates on its own. It may also prompt you that drivers are available for some of your hardware, but do the updates and reboot first.

If you can't wait, you can update it manually from the command line. To get to a command prompt, go to the Programs menu at top left and move down to Accessories, then click Terminal.

Getting down to it: Flash, Java, MP3 and so on

First, you need to tell APT to refresh its memory – to fetch the latest list of packages from the repositories. Type:

sudo apt-get update

The "sudo" command means to do this command as the SuperUser – that is, as the administrator. It'll ask you for a password; just enter your own. You'll see rows of text go past as it gets the latest info. Next, type:

sudo apt-get dist-upgrade

This will upgrade all installed software – operating system, apps, the lot – in one go. It's like Microsoft Update on steroids, only it does all your third-party apps as well. If it finds everything is already current, it will say: 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

That's a good sign. Otherwise, it will ask you for permission to continue – just say yes to everything. If you're really keen, you can manually do this yourself every day, but there's no real need – Ubuntu's update manager will check daily for you and pop up and tell you if updates are available. (This, incidentally, is one of the areas that Ubuntu and its relatives score over rivals such as Mepis and PC-LinuxOS.)

Now onto the real stuff: installing those nasty proprietary (or semi-proprietary) bits and bobs that power the fun bits of the web and so on.

sudo apt-get install ubuntu-restricted-extras icedtea6-plugin

This installs two packages, but APT automatically sucks in dozens of other requirements: the installer for the latest Adobe Flash player, Java, support for MP3, MP4 and more.

You have to admit, it's a lot easier than going to Adobe.com, downloading the Flash installer, running it, then going looking for MP3 codecs, downloading them, installing them, then video codecs – and all that.

That's it. Your copy of Ubuntu can now play MP3 or rip CDs to MP3, display web pages with Flash and Java, handle most common video formats and more.

Finally, there are a few things that are good to have, but aren't legal in some parts of the world – for instance the USA, due to the DMCA. This means have to look outside the Ubuntu standard repositories. We probably ought to insert a disclaimer here: check if you're allowed to do naughty things like watch DVDs on your own Linux computer in your country before continuing.

The easiest way to get this code – and several other useful extras – is by adding a new repository from a project called Medibuntu. The Medibuntu instructions are on the site, but in brief, copy this and paste it into your command prompt:

sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring && sudo apt-get --quiet update

After this, you can just install the last few bits:

sudo apt-get install app-install-data-medibuntu apport-hooks-medibuntu libdvdcss2 w32codecs

This adds entries for the new toys in the GUI, but more importantly, DVD support and the Windows media codecs. (If you're running 64-bit Ubuntu, use "w64codecs" instead.) Ideally, read the instructions on the Medibuntu site.

That's about it. By typing – or copying-and-pasting – just five lines, you've installed all the media codecs and components for Ubuntu to be a fully-fledged citizen of the 2010 Interweb and got past the problems that put most people off it. You should find that even locked-down stuff like Quicktime movies will play seamlessly in Firefox.

Final reminder

Apart from this stuff, remember, when it comes to doing stuff that you know how to do on Windows, don't try the same method on Ubuntu until you've had a quick look at Google to see whether it's the appropriate method.

It doesn't take long to adjust. Give Ubuntu a go for a few weeks and you may well find you don't want to go back to Windows. ®