[gora]

Попробуйте так:

Код:

@echo off

Set xOS=x64& If "%PROCESSOR_ARCHITECTURE%"=="x86" If Not Defined PROCESSOR_ARCHITEW6432 Set xOS=x86 

if %xOS%==x64 (
    if exist "%programfiles(x86)%\Mozilla Firefox\firefox.exe" (
        echo Come on...
        pause
        exit
    )
)

echo Come on 2...
pause