Mine

set OfficeX to "/Applications/Microsoft Office X/"
set Office2004 to "/Applications/Microsoft Office 2004/"

tell application "Finder"
	if (exists folder OfficeX) then
		tell application "Terminal"
			do script "Office X is installed!"
		end tell
	else
		tell application "Terminal"
			do script "Office 2004 is installed!"
		end tell
	end if
end tell