Windows (For Workgroups) 3.1(1) uses two or three primary INI files to work. THey are WIN.INI, SYSTEM.INI, and PROTOCOL.INI in the case that you have Windows For Workgroups 3.1x and have Networking installed and enabled.

[boot] - Obviously this is for how Windows boots up. It basically launches all of the basic drivers used by Windows 3.1x - those required to make it a functional GUI that actually works for the user - at boot time. This includes loading the shell, and loading drivers for I/O devices.

• shell=PROGMAN.EXE - This is the load entry for the Windows shell. in Windows 3.1x this is the "Program Manager" - ie, that huge window that fills most of the screen and has the various "Program Groups" named after the icons found inside ie "Main" "Accessories" "Games" etc. This is one you might want to edit if you get an alternative shell - of which there were many made from the early days till now - for Windows 3.1x. One of the most popular changes made is for the installation of the program "Calimira" which is a replacement shell that makes Windows 3.1 look like Windows 95 (though there are some newer variants that make it look even newer - like XP/7/Vista/etc.).
• network.drv=wfwnet.drv - basic networking driver for Windows For Workgroups. If you have plain jane Windows 3.1x you likely don't have this entry.
• mouse.drv=mouse.drvThe Mouse driver. There may be times where this is something else, but this is the typical driver used for Serial or PS/2 Mice in Win31x, as we will soon see when we get to the "description" area.
• language.dll=Likely this is for some kind of foreign language driver such as if you want to run Windows 3.1 in Finnish, Yiddish, or Japanese.
• sound.drv=mmsound.drv one of the internal "MultiMedia" drivers for Windows, not sound card specific IIRC.
• comm.drv=comm.drvSerial Port Driver - ie, those ports on the back that look like a grim robot's mouth.
• keyboard.drv=keyboard.drvBasiic driver for the keyboard
• system.drv=system.drvA "system" driver, don't change this one
• 386grabber=SVGA256.3GRThis is just one of the lines for the graphics card (which is a huge part of Windows 3.1x anyway as it IS A GRAPHICAL User Interface). This file will always be a file ending in *.3GR.
• oemfonts.fon=VGAOEM.FONOEM Fonts for Windows
• fixedfon.fon=VGAFIX.FONA "Fixed Font" is a font that has a set size and can line up - a lot like the 80x25 column ROM text mode font found in DOS, that's what this is used for I believe. It's installed when your video card is installed.
• fonts.fon=VGASYS.FONAnother video-card software installed font, this one is for the Terminal/System font.
• display.drv=SVGA256.DRVAnd here's your actual graphics driver. In this case, were using SVGA 256 Color driver. This along with the fonts and 3GR file above are all in c:\windows\system\ and installed when you install your graphics card.
• drivers=mmsystem.dll msmixmgr.dllTwo more drivers for the multimedia audio system. I think these are not there when the internal speaker is being used (pc.drv maybe?). The first one is the subsystem for audio (universal), and the other is the internal Windows mixer controls that changes levels for volume of all the I/O for the multimedia subsystem (read: NOT the specific audio card).

[keyboard] - this is a series of settings that have to do with the keyboard on your system.

• Subtype=
• type=4
• keyboard.dll=
• oemansi.bin=

[boot.description] - This largely is a set of "defines" that give a friendly name to the various hardware elements in use by Windows 3.1x.

• keyboard.typ=Enhanced 101 or 102 key US and Non US Keyboards
• mouse.drv=Microsoft, or IBM PS/2
• language.dll=English (American)
• system.drv=MS-DOS System
• codepage=437
• woafont.fon=English (437)
• aspect=100,96,96
• display.drv=ET4000 800x600 256 Small
• network.drv=Microsoft Windows Network (version 3.11)
• secondnet.drv=No Additional Network Installed

[386Enh] - This section deals with 386 Enhanced Mode settings, which is what Windows 3.1x is used in on most systems with a 386 or better CPU (including 386 SX).

[NonWindowsApp] -

• localtsrs=dosedit.ced

[vcache] -

• minfilecache=512

[mci] -

• WaveAudio=mciwave.drv
• Sequencer=msciseq.drv
• CDAudio=mcicda.drv

[drivers] -

• timer=timer.drv
• midimapper=midimap.drv
• Midi=sb16fm.drv
• Midi1=sb16snd.drv
• Wave=sb1snd.drv
• Aux=sb16snd.drv
• Mixer=sb16snd.drv

[DDEShares] -

[Network] -

• winnet=wfwnet/00025100
• multinet=nonet
• FileSharing=Yes
• PrintSharing=Yes
• LogonDisconnected=Yes
• EnableSharing=Yes
• UserName=username
• Workgroup=WORKGROUP
• ComputerName=SOMEOLD486
• Comment=Old486DX
• logonvalidated=no

[network drivers] -

• devdir=C:\WINDOWS
• LoadRMDriver=No
• netcard=pcntnd.dos
• pcntnd.dos=LOW
• transport=ndishlp.sys,*netbeui

[Password Lists] -

• *Shares=C:\WINDOWS\Share000.PWL
• username=C:\WINDOWS\USERNAME.PWL

[sndblast.drv] -

[NWNBLINK] -

• LANABASE=1

[ms$pcntn30] -

• IPMask=0.0.0.0
• IPAddress=0.0.0.0
• Descripion=Advanced Micro Devices PCNET Family
• Binding=ms$pcntn3

[MSTCP] -

• EnableRouting=0
• interfaces=ms$pcntn30
• deadgwdetect=1
• pmtudiscovery=1

[DNS] -

• DomainName=
• DNSDomains=

[NBT] -

• LANABASE=2
• EnableProxy=0
• EnableDNS=0

[svga256.drv] -

• ChipSet=VMWare SVGA2
• LatchCapable=no
• Resolution=2
• dpi=96
• svgamode=48

[windows] -

[Desktop] -

[Extensions] -

[intl] -

[ports] -

[FontSubstitutes] -

[TrueType] -

[Sounds] -

[mci extensions] -

[Compatibility] -

[winsetup] -

[fonts] -

[embedding] -

[network setup] -

[protman] -

[MS$PCNTN3] -

[MS$PCNTN3] -

[PCNTN3] -

[NWLINK] -

[MS$NDISHLP] -

[NETBEUI] -

[MSTCP32] -