INCREASE CONVENTIONAL MEMORY

To increase conventional mem in DOS
config.sys

device=c:\windows\himem.sys
device=c:\windows\emm386.exe noems
dos=high,umb


autoexec.bat

lh c:\windows\command\mscdexe.exe /D:MSCD001
lh c:\mymouse\mymouse.com

You'll need to change the path to reflect the location of your mouse driver, or anything else that might be in a different folder.
Basically, the first 3 lines of config.sys setup memory management for DOS. Drivers can be loaded 'high' in config.sys by placing

devicehigh=

at the beginning of that line. In autoexec.bat, programs are loaded high by

lh

(and a space) at the beginning of the line.

Check your DOS memory configuration by:

mem/c/p


(the 'help' program came with DOS6 - might not be available with DOS7 etc)

Not sure if a DOS4GW program actually needs memory management, but if you need more conventional DOS mem, you'll need to have a setup something like this.

480K isn't much - should be able to free that up.