@echo off

for %%i IN (e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z); do ( 
if cd %%i: (
set /p laufwerk=%%i
) 
)


try this:

@echo off

for %%i IN (c,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t); do call :TEST %%i
goto :eof

:TEST
if exist %1: (echo %1 is not a driveletter) else (echo ITS A DRIVE!! %1) & goto :eof
goto :eof