I tried both and neither worked. I have MC25 installed on two computers. I use one only for ripping cds. The other is integrated into a sound system. The one on my local computer seems to want to play correctly other than a mismatch in the frequency for the output which is unimportant. It is the system connected to the sound system that is having the issue.
I ran IE and set it as the default browser, rebooted and the same issue occurs; the 'play' arrow just expands the selection. This is running windows 7. My machine is Windows 10 which is normally a bigger issue with anything that might require permissions.
I am not sure what to do with the W7 machine. I can run the browser and it remains connected to the site, but, alas, no music.