it actually uses the same cmd window, if you leave it open you will see the "message sent" and errors show up there
if you want to a counter could be inserted in the for each that sleeps for 10 or 15 seconds for every 20 or 30 or whatever number of messages
something like:
code:
$counter=0
$msg='whatever to send'
$file=readfile('CorpPCnames.TXT')
for each $dest in $file
run 'cmd /c net send '+trim($dest) +' '+ $msg
$counter=$counter+1
if $counter=25
sleep 10
$counter=0
endif
next
