WIN /MQ automatically restarts the computer (soft reboot), without prompting or waiting for input (key press). This is similar to Quarterdeck QEMM's QuickBoot, which calls INT19h to reboot almost instantaneously (VERY FAST!) without performing any BIOS/CMOS hardware or OS/software checking.
CAUTION: This fast reboot routine may generate error messages and/or lockups!
This switch works ONLY IF executed from the native/real/true MS-DOS mode OUTSIDE the Windows 95/98 GUI, NOT from WITHIN Windows in a DOS box/session.
This DOS secret suggested by phish.

WIN /W generates this message:

"Press any key to continue...
 Pressing a key reboots back to Windows 95 (98)."

waiting for user input (key press), and then restarts the computer (warm reboot), restoring the original CONFIG.SYS and AUTOEXEC.BAT files in the root directory of the boot drive from CONFIG.WOS and AUTOEXEC.WOS (if any). This is useful when the computer is restarted after interrupting a "single" mode MS-DOS session, because of this CONFIG.SYS line:
DOS=SINGLE
which does NOT allow Windows 95/98 GUI to load.
This switch works ONLY IF executed from the native/real/true MS-DOS mode OUTSIDE the Windows 95/98 GUI, NOT from WITHIN Windows in a DOS box/session.
NOTES:

1. The .WOS files are created when you run a DOS based program that requires a separate MS-DOS reboot setup (in "single" mode), and you have selected the "Specify a new MS-DOS configuration" check box in the PIF file Properties tab.

WIN /WX automatically restarts the computer (warm reboot), without prompting or waiting for input (key press), and restores the original CONFIG.SYS and AUTOEXEC.BAT files in the root directory of the boot drive from CONFIG.WOS and AUTOEXEC.WOS (if any). This is useful when the computer is restarted after interrupting a "single" mode MS-DOS session, because of this CONFIG.SYS line:
DOS=SINGLE
which does NOT allow Windows 95/98 GUI to load.
This switch works ONLY IF executed from the native/real/true MS-DOS mode OUTSIDE the Windows 95/98 GUI, NOT from WITHIN Windows in a DOS box/session.
NOTES:

1. The .WOS files are created when you run a DOS based program that requires a separate MS-DOS reboot setup (in "single" mode), and you have selected the "Specify a new MS-DOS configuration" check box in the PIF file Properties tab.

WIN /Z automatically forces the ATX power supply to (soft-)power off the computer ONLY on ATX motherboards, without prompting or waiting for input (key press).
This switch works ONLY IF executed from the native/real/true MS-DOS mode OUTSIDE the Windows GUI, NOT from WITHIN Windows in a DOS prompt/box/session.
This DOS secret suggested by Shaminda.

WIN : starts Windows 3.xx or Windows for WorkGroups 3.1x WITHOUT displaying the startup logo (RLE encoded, 16 colors).
This switch works ONLY IF executed from the native/real/true MS-DOS mode OUTSIDE the Windows/WfWG GUI, NOT from WITHIN Windows/WfWG in a DOS prompt/box/session.
CAUTION: This switch may cause sudden lockups with some older video controllers!