To begin, you need some kind of bootable medium, preferably a floppy disk
If you have a floppy disk drive:
Create a bootable floppy, for instance by using
Start->Programs->Snapshot->Create Recover Floppy
Use A: as bootable bootable medium below
If you have no disk drive - Method A:
Method 1: create a small partition, then restore networkbootdiskette.sna (installed during setup) to this partition.
You can customize this partition at will (change autoexec.bat etc.).
Use this partition as bootable medium below.
If you have no disk drive - Method B:
Create a bootable (uncompressed) image of a floppy.
Using the windows commandline, expand networkbootdiskette.sna with the (undocumented) command
c:\programs\snapshot> snapshot networkbootdiskette.sna bootdisk.img -X
Use bootdisk.img as bootable medium below.
Better now then in an emergency ;)