What you need to have in order to make your system work

A soundblaster card (or clone) installed, preferably in its
default configuration. (Address 220, Interrupt 7, DMA channel 1)

\NT\DRIVER\SNDBLST.SYS present

\NT\CONFIG\SYSTEM.REG with the line SNDBLST.SYS
This file should not end with CRLF.  The easy way to avoid
this is to insert the SNDBLST.SYS line as the NEXT TO last line.

C:\NT\WINDOWS\SYSTEM\MMDRV.DLL present

C:\NT\WINDOWS\SYSTEM\WINMM.DLL present

C:\NT\WINDOWS\SYSTEM\MCISEQ.DLL present (for MIDI)

C:\NT\WINDOWS\SYSTEM\MCICDA.DLL present (for CD Audio)

C:\NT\WINDOWS\SYSTEM\MPLAYER.EXE present (Media player)

C:\NT\WINDOWS\SYSTEM\SOUNDREC.EXE present (Sound recorder)

C:\NT\WINDOWS\SYSTEM\SOUND.CPL present (Control panel applet)

system.ini containing:
;-----------------------------------------------------------------
;
; This section associates a MCI media type with a MCI media driver
;
[MCI]
    WaveAudio=mciwave.dll
    Sequencer=mciseq.dll
    CDAudio=mcicda.dll

[drivers]
    wave=mmdrv.dll
    midi=mmdrv.dll
    midimapper=midi.cpl
;-----------------------------------------------------------------

win.ini containing:
;-----------------------------------------------------------------
[MCI Extensions]
    Wav=WaveAudio
    rmi=Sequencer
    Mid=Sequencer
;-----------------------------------------------------------------

In addition, you might want to
ERASE c:\nt\windows\MPlayer.INI
as MPlayer can somethimes think that it KNOWS that there are
no drivers of a particular sort on the system, with the result
that it fails to look.  A dose of enforced amnesia can help it.

You might want to have some corresponding icons in PROGMAN
(File; New; Program Item; etc)

You do not need a MMDebug section to make your system go, but if
you want to see debug output you could try (in Win.ini)
[MMDebug]
    SoundRec=3
    MPlayer=3
; choose a value in the range 0 (no output) to 4 (E-V-E-R-Y-T-H-I-N-G)