Microsoft ended support for Windows XP almost a year ago… and it still has more users than Windows 8

Nothing wrong even if it's connected to the internet, provided it's behind a router and using NAT:

As others have pointed out, NAT is not a security feature. However, it does offer some level of security as a byproduct: a side-effect of NAT is that none of the inner machine is accessible "from the outside". The same effect can be achieved by a firewall which blocks all incoming connections. This is not fine-grained, but rather effective in practice, and if NAT did not come with that "automatic" protection, a lot more existing networks would be attacked and zombified into spam relays (that's the scary point about IPv6, by the way: IPv6, when [if] widely deployed, will have a tendency of nullifying the protection effect of NAT, and one can expect an average increase of attack success). http://security.stackexchange.com/questions/8772/how-important-is-nat-as-a-security-layer

If you are behind a router then not outside computer can connect to your computer. By default incoming connections are blocked. The idea that you needed to run a firewall and have all the latest patches stems from the practice of not using a router in the consumer space back in the day. Your computer was hooked up directly to the modem and it let anything in. You would receive constant attempts to hack into your computer and this is how the latest patches protected you.

I distinctly remember that my mother-in-law had this problem. Constantly getting hacked. I installed a $10 router just for the NAT and all of that stopped. She never got hacked again. Now, you can still get viruses and malware, etc. but that vulnerability is not about the OS but about the software that is initiating outside connections, e.g., your browser or email client. This has nothing to do with the OS at all regarding vulnerability.

tl;dr: it's best to have the latest MS OS but if you are behind a router then you are almost as safe.

/r/windows Thread Parent Link - bgr.com