Leona+

string value64 = string.Empty;
string value32 = string.Empty;

RegistryKey localKey = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry64);
localKey = localKey.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion");
if (localKey != null) {
    value64 = localKey.GetValue("RegisteredOrganization").ToString();
}

RegistryKey localKey32 = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry32);
localKey32 = localKey32.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion");
if (localKey32 != null) {
    value32 = localKey32.GetValue("RegisteredOrganization").ToString();
}

public enum RegSAM {
    QueryValue = 0x0001,
    SetValue = 0x0002,
    CreateSubKey = 0x0004,
    EnumerateSubKeys = 0x0008,
    Notify = 0x0010,
    CreateLink = 0x0020,
    WOW64_32Key = 0x0200,
    WOW64_64Key = 0x0100,
    WOW64_Res = 0x0300,
    Read = 0x00020019,
    Write = 0x00020006,
    Execute = 0x00020019,
    AllAccess = 0x000f003f
}

public static class RegHive {
    public static UIntPtr HKEY_LOCAL_MACHINE = new UIntPtr(0x80000002u);
    public static UIntPtr HKEY_CURRENT_USER = new UIntPtr(0x80000001u);
}

public static class RegistryWOW6432 {

    [DllImport("Advapi32.dll")]
    static extern uint RegOpenKeyEx(
        UIntPtr hKey,
        string lpSubKey,
        uint ulOptions,
        int samDesired,
        out int phkResult);

    [DllImport("Advapi32.dll")]
    static extern uint RegCloseKey(int hKey);

    [DllImport("advapi32.dll", EntryPoint = "RegQueryValueEx")]
    public static extern int RegQueryValueEx(
        int hKey, string lpValueName,
        int lpReserved,
        ref uint lpType,
        System.Text.StringBuilder lpData,
        ref uint lpcbData);

    static public string GetRegKey64(UIntPtr inHive, String inKeyName, String inPropertyName) {
        return GetRegKey64(inHive, inKeyName, RegSAM.WOW64_64Key, inPropertyName);
    }

    static public string GetRegKey32(UIntPtr inHive, String inKeyName, String inPropertyName) {
        return GetRegKey64(inHive, inKeyName, RegSAM.WOW64_32Key, inPropertyName);
    }

    static public string GetRegKey64(UIntPtr inHive, String inKeyName, RegSAM in32or64key, String inPropertyName) {
        //UIntPtr HKEY_LOCAL_MACHINE = (UIntPtr)0x80000002;
        int hkey = 0;

        try {
            uint lResult = RegOpenKeyEx(RegHive.HKEY_LOCAL_MACHINE, inKeyName, 0, (int)RegSAM.QueryValue | (int)in32or64key, out hkey);
            if (0 != lResult) return null;
            uint lpType = 0;
            uint lpcbData = 1024;
            StringBuilder AgeBuffer = new StringBuilder(1024);
            RegQueryValueEx(hkey, inPropertyName, 0, ref lpType, AgeBuffer, ref lpcbData);
            string Age = AgeBuffer.ToString();
            return Age;
        }
        finally
        {
            if (0 != hkey) RegCloseKey(hkey);
        }
    }
}

string value64 = RegistryWOW6432.GetRegKey64(RegHive.HKEY_LOCAL_MACHINE, @"SOFTWARE\Microsoft\Windows NT\CurrentVersion", "RegisteredOrganization");
string value32 = RegistryWOW6432.GetRegKey32(RegHive.HKEY_LOCAL_MACHINE, @"SOFTWARE\Microsoft\Windows NT\CurrentVersion", "RegisteredOrganization");