I was really trying hard to fix this problem, I was with the same problem:
1.11.2017 09:30:16: Discord exception: System.DllNotFoundException: Unable to load DLL 'discord-rpc': The specified module could not be found. (Exception from HRESULT: 0x8007007E)Then, i tried "Visual C++ Redistributable for Visual Studio 2015 (x64)" then didn't work, so i realized that Osu! and Discord run at 32 bits, then i downloaded the (x86) too and restarted my PC, now it's working well!
I also said to a friend of mine to make the same thing, and it worked for him as well!
So, if you didn't tryed it yet, here's the download link:
https://www.microsoft.com/en-ca/downloa ... x?id=48145