#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "[A-Z]:.*\.\w+"
Local $sString = ""msqlsum81pv 0 0 25 25 25 2 -sn D:\\workdir\\PV 81\\config\\sum81pv.pwf -C 5000""
Local $sSubst = ""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm