[autoit]
#include <File.au3>
#include <Array.au3>
Local $aRecords
_FileReadToArray("dings.txt", $aRecords)
_ArrayDelete($aRecords, 0)
For $i = 0 To UBound($aRecords) - 1
$aRecords[$i] = StringReplace($aRecords[$i], "Kabelanschluss", "High Speed", 1, 1)
Next
_FileWriteFromArray("dings.txt", $aRecords)