I just got a new Mac and I need Flash Player but it won't install. It gets as far as 97% (sometimes) and it says it can't install because Safari is open and needs to close. Safari is closed but it still won't install. Can anyone please help me ASAP?
On Mac's closing a browser (or any application) window, doesn't actually close the application, it simply closes that window, so if you're just closing the window, the application is still running. You need to ensure Safari is closed/terminated before installation will proceed. Please see How do I quit Safari (or another browser/app) in OS X.
I don't believe Macs support Flash anymore, and you may have to look on their website as to how to deal with its absence.
Not sure where you got your "I don't believe Macs support Flash anymore" info from, but it isn't true. Flash Player is not, and has never been, supported on i-Devices, but has been, and continues to be, supported on OS X. If you have a valid source stating your claim, I'd love to see it.
Have a great day.