Just so you know, when you are inevitably forced to either abandon the internet or Windows 7 in a few years, if Windows 10 is still the thing at that time, you can use it without paying for it. Windows 10 gets updates even if it's not activated. The only issue with not paying for Windows 10 is that you have a transparent watermark in the bottom right corner of your primary display and you don't have the ability to change your background without workarounds.

In regards to Windows 7 and Quickbooks 2017, although I do not use that combination, I don't see any reason it would not work well unless as QB says, it's a Windows issue.