The Windows 7 release date is fast approaching, you'll be able to get hold of your copy on 22 October. But you can save money by buying it earlier - read on to find out how.

This time last month, Microsoft was still saying UK buyers would get Windows 7 E - a version of Windows 7 without a browser to avoid censure by the European Commission.

But Microsoft has now changed its mind and will ship the same versions of Windows 7 that it will across the rest of the world.

Once you have installed Windows 7 you will then be able to choose which browser you want.

Microsoft has yet to clarify its European Windows 7 upgrade strategy apart from saying it will offer Full Packaged Product (FPP) upgrade editions of the OS in due course.

However, we don't need to worry too much about that - because of its mess-up with Windows 7 E, Microsoft is currently offering full versions of Windows 7 in the UK for the price it was going to offer the upgrade versions.

This will change on 1 September, when Windows 7 Upgrade versions will be available alongside the full product version and things will get more expensive.

So before the end of August, there's little reason not to go out and buy a copy now; we're currently being charged around half the price for a full copy of Windows 7 Home Premium as our American counterparts.

Windows 7 Home Premium is currently for sale at £65 on Amazon, £75 on Play.com.

The 3-license Windows 7 Family Pack will also be available for £150.

How to upgrade

So what are your options for upgrading your current machine to Windows 7?

If you've recently bought a PC with a copy of Windows Vista Home Premium, Business or Ultimate, you'll have been given a Microsoft Offer Form Code. You need to go and register for your Windows 7 upgrade.

For anybody else, read on. Despite the usual criticism of Microsoft's multiple-version Windows releases, it actually isn't that complicated.

You can upgrade from a particular version of Windows Vista to the equivalent version of Windows 7, while an Ultimate Edition of Windows 7 can be installed over any version of Vista.

It's still unclear whether Microsoft will launch the three-license Family Pack in the UK, even though the axing of Windows 7 E means the situation has changed from when Microsoft originally said it wouldn't be available in the UK.

In the shops and online, you'll have the choice between boxed copies Windows 7 Home, Professional and Ultimate, while netbook manufacturers can also deploy Windows 7 Starter Edition – a cut-down and frugal version of the OS.

Windows 7 upgrade

No versions of Windows XP can be upgraded – you'll need to do a clean install, as you will with 32-bit to 64-bit upgrades or, indeed, if you're upgrading a version of Vista to a lesser version of Windows 7 – for example Ultimate to Home Premium.

Microsoft has produced a video showing you how to move your settings and files to your new Windows 7 install with the advanced User State Migration Tool. You could also try out the Belkin Easy Transfer Cable.

If you've been using Windows 7 already, you might know that you could upgrade to the Windows 7 RC (Release Candidate) from the beta with a small fix. With another tweak you can upgrade from the Windows 7 RC to the final release, but only with the Ultimate Edition – as that's what the Beta and RC versions actually were.

However, if you have been using one of these pre-release versions Microsoft recommends a complete reinstall.

By the way, if you've been a invitation-only member of the Windows 7 Technical Beta Program, you're entitled to a free copy of Windows 7 Ultimate Edition.

Upgrade between Windows 7 versions

If you want to upgrade from one Windows 7 version to another at a later date, you can do this as well using Windows Anytime Upgrade. This isn't a particularly cheap way to get a better version of Windows 7, but does mean that if you buy a Windows 7 netbook with Starter Edition you can upgrade it to a more capable version.

However, we'd expect that many netbooks will eventually carry better versions of Windows 7 than Starter Edition.

Microsoft says – and our tests back this up – that in general, if your PC can run Windows Vista, it can run Windows 7. But if you want to check it out, the Windows 7 Upgrade Advisor will tell you if your PC can run Windows 7 and if there are any known compatibility issues.

Windows 7 will run on surprisingly underpowered machines – we've had the Ultimate Edition running on quite modest desktops and netbooks.

If you want to install it on a netbook, check out our guide to installing Windows 7 with a USB key (if you don't have an optical drive you can use).

Remember that if you are upgrading your OS (and certainly if you're performing a clean install) you absolutely MUST back up your system.

When compiling this guide we asked Microsoft to clarify its upgrade options. It says it will be making "an announcement shortly" about upgrade editions of Windows 7, so watch this space.

-------------------------------------------------------------------------------------------------------

Liked this? Then check out 62 seriously useful Windows 7 tips, tricks and secrets

Sign up for TechRadar's free Weird Week in Tech newsletter
Get the oddest tech stories of the week, plus the most popular news and reviews delivered straight to your inbox. Sign up at http://www.techradar.com/register

Follow TechRadar on Twitter