what's a bit strange is that it worked and then now doesn't .... it seems like it started when you enabled DLNA. However maybe your Windows default device is not set too. I agree tho, do not go over to Win10 before you get this up and running.
If you haven't already please read this it will help =>
http://wiki.jriver.com/index.php/Audio_Setup Even though, normally, the first choice is to use the native drivers for your Dac, in this case ASIO. I'd try simplifying.
Then you can add back somethings later.
I'm assuming you have only 1 zone set up now .. the default one called "Player"
I'd try to be as "default" as possible ..
In Options =>Media Network=>"Use Media Network to share ..." is disabled
In Options=>Audio (zone to configure = Player) set Audio Device to a WASAPI device (probably a realtec driver? -- also make sure this is the playback device selected in Windows=>Sound=>Playback devices) whatever can be correctly connected to your external DAC
In Options=>Audio click the 3 "..." to open device settings and verify defaults are set ... check allow exclusive access, Bit Depth on Automatic, buffering at 100ms
In Options=>Audio=>Advanced=>Live Latency verify the default is set at 50ms
Now in Options=>General Features uncheck WDM driver if enabled.
Close down MC (making sure there is no media server program running - see icons at bottom right of windows task bar and shut it down if needed.
Re-open JRiver and test. Does this play? It should. If this worked, then we can try changing the audio device to your Dacs ASIO driver to se if it sounds better .. then if this works, you can get JRemote running .... finally if you want to use the WDM driver, set this up last (BUT highly recommended to do this in a different zone.
Note: when set to exclusive playback (better for many reasons), as I see you have a "gaming" DAC, if JRiver is loaded, it is normal that you will not have sound from you tube, other external programs... don't freak out. Just close down JRiver for the moment is a test config, not necessarily the best adapted to your use.
hope this helps
PS- 30% CPU load is pretty high ... did you mean total load or what JRiver was taking? ... On one fo my older PCs -- during playback I'am showing 0.9% CPU load for JRIVer (with some spikes of course)