If your running Windows 7 or above and you've found a new icon that has appeared in the Task Bar over near the clock (the System Tray). When you hover the mouse over it the text reads Get Windows 10, as shown in the image below.

Is it a virus?

No, it's just Microsoft letting you know that their new Operating system is available.

The good news is that Microsoft is offering free upgrades to everyone who is currently running legal copies of Windows 7, Windows 8 and Windows 8.1.

Is there a catch?

Yes, you have to get the upgrade within 12 months of Windows 10 being released (July 2015).

What happens if I need to re-install Windows 10 after July 2016?

You still have a valid license for Windows 10 and and can re-install it any time without having to pay anything to Microsoft.

What happens if I don't want the free upgrade, how do you get rid of the icon?

Because Microsoft is getting more agressive with pushing Windows 10 and we all know that not everyone is comfortable upgrading, there is an application that has been developed by Steve Gibson from grc.com called Never10. This utility uses the Microsoft recommended method for stopping Windows 10 being upgraded, plus gives you the option to remove any of the upgrade files that have already been downloaded and also gives you the option enable the Windows 10 upgrade again.

You can find Never10 from here: https://www.grc.com/never10.htm