If you have Windows 7 or 8.1 then you are entitled to a free upgrade to Windows 10, it is very rear that Microsoft gives out free things like this! I have been playing with the early release of Windows 10 and it does look to be a great product, I would say it has the best of both worlds, ie if Windows 7 and 8.1 had a baby it would be called Windows 10.
As of 1st of June Microsoft have announced that Windows 10 will be available to eligible Windows 7/8.1 users in early August. This is a lot earlier than anticipated.
From today onwards, you may notice a little POP UP icon come into your computer down by the clock, it will tell you about the advantages of Windows 10 and you can then choose to opt-in for the free upgrade. Once accepted you will then get the upgrade via Windows Updates (its a massive 3GB!!) in August when it is ready from Microsoft.
I am both excited and nervous about this new release, nervous because I can imagine quite a few computer users getting a fright when they boot up their computer in August to find every thing has upgraded and changed. But I am excited that Microsoft has listened to their customers and created what looks to be a top operating system. Time will tell....