Windows 10, the latest version of Windows, will be released on 29th July. The new Windows OS has received rave reviews from people who are currently testing it as part of the Windows Insider program but there has been some confusion around the upgrade path. Will you be eligible to download a free upgrade of Windows 10 or will you have to pay for the license?
Free Windows 10 Which versions of Windows will get a free upgrade to Windows 10?
To find out which version of Windows you have, open Control Panel and go to System. The precise Windows version will be listed. It doesn’t matter if it’s 32- or 64-bit.
Alternatively, click here to see which version your computer is running. 
Only the following versions are eligible for the update:
These versions are not eligible (some merely require updating to the versions above):
  • Windows 7 RTM (this can be updated to SP1 for free)
  • Windows 7
  • Windows 8 (this can be updated to 8.1 Update for free)
  • Windows 8.1 RTM (this can be updated to 8.1 Update)
  • Windows RT (the version of Windows used on the Microsoft Surface and Surface 2 – cannot be updated)
  • Windows Phone 8.0 (updates may be available from your mobile operator or Microsoft)
In terms of specific versions, the upgrade will work on a “like-to-like” basis:

Upgrade from Windows 7:

From Edition
To Edition
Windows 7 Starter
Windows 10 Home
Windows 7 Home Basic
Windows 7 Home Premium
Windows 7 Professional
Windows 10 Pro
Windows 7 Ultimate

Upgrade from Windows 8:

From Edition
To Edition
Windows 8.1
Windows 10 Home
Windows 8.1 Pro
Windows10 Pro
Windows 8.1 Pro Student
Windows 8.1 Pro WMC
Windows Phone 8.1
Windows 10 Mobile

What about Windows 10 Insiders testing the preview builds?

A new development is that Microsoft has annnounced that people running the preview version of Windows 10 will get upgraded to the final version for free. There are two options here. If you clean installed the Windows 10 preview, then you'll need to continue on the Insider program and receive future builds and updates to test and try out before the are released to the general public.
This means there is a kind of loophole by which you can have a copy of Windows 10 even if you don't own a version of Windows which qualifies for the free upgrade. You will have to install a Windows 10 preview build before 29 July, though. Microsoft's blog clarifies that this is not intended to be a path by which you can freely upgrade your XP or Vista machine, though.

If you upgraded a genuine qualifiying version of to the Windows 10 preview, you can get the final version on 29 July and then opt out of future preview builds and simply enjoy Windows 10. However, if you wiped your hard drive to install the preview, you will have to opt in to the updates, or reinstall Windows 7 or 8.1 in order to get the upgrade to Windows 10.

What are the system requirements for Windows 10?

Just because your computer, tablet or phone runs one of the eligible versions of Windows doesn’t guarantee it will get the update. There are some hardware and software requirements as well.
These are the minimum hardware specifications needed to run Windows 10:
  • Processor: 1GHz or faster processor
  • RAM: 1GB for 32-bit or 2GB for 64-bit Windows 10
  • Hard disk space: 16GB for 32-bit or 20GB for 64-bit
  • Graphics card: DirectX 9 or later
  • Display: 1024x600 pixels or higher (virtually all devices have this)

Will I lose my files and programs by upgrading to Windows 10?

Your files, settings and applications will be kept, but some settings and applications won’t be ‘migrated’ as Microsoft puts it.
For example, anti-virus software won’t be moved. Windows 10 should keep your anti-virus settings and install the latest version of your AV software after the update, assuming your subscription is current.
If it isn’t, Windows Defender will be enabled instead.
Other apps which may not be moved include those installed by your computer manufacturer, as well as those which aren’t compatible with Windows 10.
As before, you’ll get a list of any such issues before beginning the actual update, so you can choose whether or not to proceed with it. Most applications which run in Windows 7 and 8 will work fine in Windows 10, so there shouldn’t be many problems in this area.

Windows 10 upgrade: Which features will I lose during the update?

You will lose some apps, games and features. For a full list see Worst Windows 10 sacrifices

Windows: 10 upgrade: Will I get Cortana, Windows Hello and Continuum? 

Cortana will be available on Windows 10 for the United States, United Kingdom, China, France, Italy, Germany and Spain. For speech recognition you will need a microphone of course, but for “better speech experience” you will need a ‘high fidelity microphone array’.
Windows Hello is a new way to log into the OS using facial recognition or a fingerprint. For that, you’ll need either a special infrared camera or a fingerprint reader which supports Windows Biometric Framework.
Continuum is where Windows 10 will switch between laptop and tablet modes. There will be a manual switch in all Windows 10 editions, but on some devices it will switch automatically, or be configurable to switch automatically.