1. See the requirements section at
http://msdn.microsoft.com/en-us/library/windows/hardware/ff551963(v=vs.85).aspx[
^]. This function is available on Windows Vista and above. You will also need to have the DLL on the system, I don't think it comes as standard, which is why VS is also required.
2. You probably can, but the Setup functions sometimes need to do more than just reading the registry, so you are generally advised not to rely on it.
3. Sorry, don't know.