Definitely Windows 7. Avoid Windows 10 as long as possible.

Windows 10 forces updates on you, even hides their size. Every few months, huge OS updates will slow down your PC, reset many of your system settings, reset app defaults, put back many of the apps you removed, remove some of the apps you might be using and act like you have no control at all.

The features in Windows 7 are also more suitable for desktop usage compared to Windows 10 where the focus is more on pushing you to the cloud or to mobile Store apps made to work crudely on a desktop. There are ads in some apps, 90% of features are missing in these dumbed down mobile apps and the OS promotes some apps to you in your face, and generally acts all hostile. Windows 10 is basically a productivity, usability and manageability failure. The GUI is a mess, and you never feel like you can make the system work the way you want - every few months everything is reset since Microsoft wants to turn the OS into a service. Windows 10 also spies on everything you do so they can 1. Sell your info to advertisers who target you with ads 2. Eliminate any settings that *they think* people don't need 3. Send your info to Bing to generate revenue for themselves like how Google earns money. 4. Sell the OS as a perpetual subscription to enterprises, and possibly in the future to consumers as well. Windows vista
If being in control of the OS on your PC is what you are after and you like having options and choices, then Windows 7 is what you should stick to.

I would also recommend Windows 8.1 free download with Classic Shell and a dozen other desktop programs to fix it if you think Windows 7 is outdated. But you must know where to find the right apps for 8.1 since out of the box, it is also a very bad user experience, although it can be fixed. I am finding Windows 10 unfixable and would never use it.

Just a rebuttal to some of his points: I would agree that for a power user windows 7 is probably the way to go. However:

1. no one is forcing you to use the 'apps' environment, you can run windows 10, almost entirely without even touching it (after changing a few system defaults for certain files)
I personally hardly ever use Apps.. but it is an added layer that windows 7 does not have.. (better if your not using them

2. Yes a considerable portion of apps have ads, but in-general they are safer, from malware, and viruses... because of the locked down nature, and Microsoft's ability to police the app-store bootable usb windows 7

3. I haven't personally had any apps (I have only installed about 20 different custom apps) get deleted after an update. But Id imagine that If one were removed from the app-store, it would potentially be removed locally too (Though the Ideal would be to prompt the user "This app was removed from the store because: X, It may be unsafe to keep. Would you like to remove it?" instead of just removing it

4. I haven't had any apps restore themselves either, though Ive only removed a few 'get Office', ect. I cant Imagine an average user caring enough to remove apps that have virtually no impact on the system when not in use.. (except a small bit of hdd, and some clutter in the apps folder)

5. Yes windows 10 is hella spyware, but pretty-much all of that can be blocked: http://softlay.net/operating-system/windows-7-download.html(Yes you shouldn't have to; block it, but at least you can)


Also It should be noted that mainstream support has already ended on windows 7, which means that the only updates will likely be security ones. and even that ends in 2020 (though another 4 years is a while for a PC)


Bottom line: Though both mentioned OS's will run fine with your specs. If you planned on dropping 120$ on an upgrade. You might consider a Used PC, because you can get a faster used pc, with windows 7 or 10 pre-installed for around that price point.