to save game in multiplayer mode, you can copy file 
c:\windows\hrinfo_x.drv (x: 0,1,2,3,4....). But note: you 
will lost you character if you reinstall windows. You can 
rename any file c:\windows\hrinfo_x.drv to c:\windows\dlinfo_drv, 
your character will appear in multiplayer mode of DIABLO 
(note: before rename file, you sure that inventory of your character 
is empty, and character name not same any name in DIABLO)