I don't want speak badly about upgrade paths but MS does this every time they have board meetings to hash out the upgrade path and pricing index. They have a huge development team that decides what features stay and what features disappear. Sometimes it's by accident, most the time it's for more money via support calls and upgrade features $$$...
I always do a fresh install of my OS, that is my suggestion to you. If their licensing allows you to fresh install it and only give your previous activation number from the other os as proof (which they did in the past) then you can go that route.
Now for the real tech help ---
1) Right click on speaker icon in the lower left on the desktop (to get to the desktop from the metro menu hit winkey+D ).
2) Select "playback devices"
3) Find the SPDIF out playback device that goes to your Samsung receiver. If you have multiple SPDIF out right click on each one and hit "TEST" until you hear it come out of the correct speakers. No right click on the correct SPDIF out and select properties.
4) In properties check "Sample Rates" and make sure 48khz or above is selected and be aware that selecting a very high rate like 192mhz may not be support by your equipment. My Sony receiver supports only up to 92khz stream but I have the option to select 192khz.
5) In the properties section check the "Ecoded Formats". You should be able to select and test what your receiver can support, test each one and select the ones that work, un-select the ones that do not.
----------The real in depth super complex tech info
During the upgrade, it dumps a bunch of log files and depending on checks and licenses and various unkown and undocumented features the installer may or may not disable audio features that are "built-in" to windows. These features have never had to be added, they have always been there but a setup program just removes the entries and disables the features then they put an add in the media player suggesting you pay for the features that you already paid for. Lovely right?
For example here is something from a windows 8 log upgrade
common\mfplayer.cpp:2619: ConstrainCodecs: ... Disabling transform "Microsoft Dolby Digital Plus Decoder MFT" with CLSID [177c0afe-900b-48d4-9e4c-57add250b3d4].
As you can see, it's built-in and it has a CLSID associated with it, with a proper registry import you could get your functions back but you would need to have someone graciously donate a registry dump with all the formats enabled. The community that knows about this are generally very hostile toward people asking for such information so you chances of finding real help are very low.
Now for the good news, an open source project called "Media Player Classic HD" has certain features built into it to completely bypass windows audio transform mechanisms and feed raw data straight to your spdif. You will have to do some research but it's really easy to set up the audio out to spdif only on MPCHD and if your DVD has 5.1 or 7.1 support it will be detected and decoded.
Otherwise you may end up having to pay for a feature already built in because MS decided to make all the money on the media side this time around. 36$ For one season of TV? WOW! If could afford it I would pay it, but I will stick with general streaming services. Thanks. I mean if I am going to pay 36$ for a season pass to watch one season of a TV series why not just buy the dvd's and lug them around in a big suitcase? I think they need to rethink their pricing model. Their apps and games are priced fairly, but the media price is extremely limiting. I calculated it would cost me over 10,000$ to catch up all the movies and TV I missed last year with their store. Really? I would rather pay for a trip to an Asian island that lets you get high legally the whole time your there, money well spent.