I just got my old Soundblaster Audigy SB0090 kind of working to play music on Windows 10 release 2004.
I downloaded the file, [ SBA5_PCDRV_L11_3_01_0056B.exe ] this is a .exe file , self extracts then goes to Instalshield, and falls over because the RX card is not present.
Then I went to $WINDIR\TMP and look for a CRF folder (CRF003 in my case) and then go to the folder "Audio\DriversWin10" and execute "setup.exe" and make sure to select "Overwrite existing shared Creative
audio files", wait and after it finish restart the PC.
Then plug the speaker into the green jack, open Sound settings and, (this is kind of weird point) instead of Speakers (Creative SB Audigy) select SPDIF (Creative SB Audigy) as default
output, and you should get sound out of the speakers if not, try some other Creative SB Audigy options.
Now the sound might not be too good because the internal volume is setup to 100%, so make sure you go to "Advanced Sound Options" and lower the volume of the different applications, to avoid sound distortions by saturating
the audio channels.
I do not guarantee that it will work for everybody, but it did for me, and I thought to share just in case it ever helps somebody.