I use donetfx.exe with arguments /q:a /c:\"install /l /q\"" in silent install

in ams7 is:

result = File.Run("Windows\\dotnetfx.exe", "/q:a /c:\\\"install /l /q\\\"\"", "", SW_SHOWNORMAL, true);

but no run to silent istall

what is the problem?? please help.
what i have do it?