exchange drive-letters in win95b

i dont remember anymore if i ever had the drive-letters right on my win95b-hdd. there was an ms-compatibility-problem(old question). i changed letter in config-sys from z to e. i have c(hdd), d(cd-rw-burner) as secondary master
plus e(first slave). would like to have d and e exchanged. its impossible enter/changing any letter in system/devicemanager.

maybe in config.sys(where cd-rom-driver is mentioned)i should set from E to F(last E +1), right?

then change letters. what should i set asfirst and last letter for each drive?