Windows 7 and Windows 8 users get a free upgrade to Windows 10. But you don't have to upgrade right away. You have a full year. (Until July 29, 2016.) So you can upgrade at your leisure and not waste a bright, summer day doing it.
You're using Windows 7
Windows 10 undoes a lot of the damage done by Windows 8, an operating system that was built more for touch devices than for traditional PCs. In fact, two of Windows 10's big improvements over Windows 8 are the addition of a Windows 7-style Start menu and the ability to work entirely on the desktop and ignore the touch-focused Start screen.
So if you currently use Windows 7, you're already set. You already have a Start menu and you work only on the desktop.
In short: If you're happy with the way Windows 7 works, you may want to stay with it for now.
Security updates for Windows 7 and 8 will be available for years!
Microsoft has a habit of pushing people to its latest operating system by ending support for its old operating systems, halting security updates and leaving users potentially open to security threats. If you have Windows 7 or Windows 8, you've got years before that happens. Microsoft will keep issuing security patches for Windows 7 until January 2020 and for Windows 8 until January 2023
You don’t have to upgrade. Remember, if you’re using a Windows 7-based PC, you’ll likely want to upgrade to a new PC by then anyway
You have old peripherals
The Achilles heel of most new operating systems is handling older peripherals, such as printers and scanners. Microsoft doesn't always make sure that drivers for vintage devices work with the new operating system -- it would take too many development resources. As a result, some of these peripherals won't work with newer operating systems.
So if you have old favorites with a lot of mileage on them, don't upgrade right away. Scour the Internet for news of whether they work with Windows 10, and only upgrade to it when you know that they do.
No ActiveX Support
For those of you in the habit of accessing your security cameras, etc. via the included Active X interface popular with most brands of camera, you will no longer be able to use your Windows PC to access them.
Although your phone will still continue to work with your cameras, Windows 10 has dropped all ActiveX support due to the potential security compromises with it.
Future major upgrades could leave you without a valid copy of Windows!
Users are already reporting that after upgrading their CPU or Motherboard, Windows 10 complains that their FREE license is now invalid, forcing them to go and purchase Windows 10 to continue.
(Some users have been successful in contacting Microsoft to "re-validate" their Windows license after this happens)
OUR ADVISE? - WAIT FOR A MORE STABLE RELEASE.
If you’re still willing to take the plunge (as millions already have), go ahead.
If you DO run into issues, we’ll be here for you - and we’ve got the experience to help you!