I always stay with the newest operating system (someone has to volunteer). Notes from a life-long IT geek:
XP was a good OS for a long time....but, that time is long gone.
Completely agree. Although there are a few big companies out there still transitioning to Win 7.
As far as Win 7 vs. Win 8.... They're practically the same if you don't use the new tiled screen of Win 8, which I completely ignore. The biggest complaint folks have is the missing start button which I replaced with this free app:
Classic ShellEDIT: Another feature people do not like is using a Microsoft Account to log in to Windows vs. a standard login on Win 7 and earlier. There are ways to work around this too. Microsoft implemented that so you could buy apps on their App Store. This is similar to the app stores of Apple and Android/Google.
Not so sure about 8.1; haven't had to tinker with it much.
Win 8 vs. Win 8.1 - No noticeable differences.
And is Windows Defender on Win8 as good as the Avast AV that she is now using?
Win 7 had Security Essentials included which was Microsoft's built in solution. They changed the name to Windows Defender on Windows 8 but it's basically the same app. It suits my needs as a free built-in tool and I only reach out to a separate app if I think I've got some virus/spyware funk which is very rarely. I also keep my internet locked when I'm not on the computer with an old free software tool called Zone Alarm.
If anyone has any questions regarding newer operating systems, let me know. BIAB & RB work well on Win 8.1.