Ok so you are doing a downgrade, have not used xp in years so cant vertify officexp registry location but
you could do the error level as suggested via a reg query as follows
Untested but you can get general idea
Code:
@echo off
:Ck for O2Pro First
reg query HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\%ProductName% 1>> "%LogLocation%\%computername%.txt" 2>>&1
set Level=%ErrorLevel%
echo Error Level=%Level% >> "%LogLocation%\%computername%.txt"
if %Level%==0 (goto End) else (goto OfficeStd)
REM If 1 returned, the product was not found. Run setup here.
:OfficeStd
"%DeployStd%\setup.exe" 1>> "%LogLocation%\%computername%.txt" 2>>&1
echo %date% %time% Setup ended with error code %errorlevel%. >> "%LogLocation%\%computername%.txt"
REM If 0 or other was returned, the product was found or install was succesfull.
:End
