CWebbrowser(1) IE3/IE4

I want to have an application with the webbrowser ActiveX CWebbrowser for IE3 and CWebbrowser1 for IE4. How can I find out what IE is installed on the PC?

BOOL _IsIE40()
{
BOOL bfRC = FALSE;
RegistryKey orkVersion("HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Internet Explorer" );
TCHAR *ptcTemp = orkVersion.Value( "Version" );
if ( ptcTemp ) {
ptcTemp[ 4 ] = '\0';
double dlVersion = atof( ptcTemp );
bfRC = ( dlVersion >= 4.71 );
free( ptcTemp );
}
m_bfIsIE40 = bfRC;
return bfRC;
}

What is RegistryKey? Is that not Java?

Wayne