To make extended memory available you will need to load an
extended memory manager (HIMEM.SYS or equivalent).
The simplest way of loading HIMEM.SYS is to add the following line to your
CONFIG.SYS file:
DEVICE=HIMEM.SYS
But that is assuming that you have the file HIMEM.SYS in the root of the drive
you are booting from. With Windows 9X you will probably require:
DEVICE=C:\WINDOWS\HIMEM.SYS
With prior versions of DOS the file was in the DOS directory so you'd need:
DEVICE=C:\DOS\HIMEM.SYS
You may need to use some parameters as well, look up HIMEM.SYS in my DOS Reference
for more details.
To make expanded memory available you will need to load an expanded memory
manager like EMM386.EXE (you need to load HIMEM.SYS first). You can load
EMM386.EXE simply by adding:
DEVICE=EMM386.EXE
To you CONFIG.SYS file. This example again assumes that EMM386.EXE is in
the root of the drive you are booting from, if not you will need to specify its
location as before (normally C:\WINDOWS\EMM386.EXE on Windows 9X machines).
Once more you should look up HIMEM.SYS in my DOS Reference
for more options.