Get MAC address of your system

public string GetMACAddress()
{
    ManagementClass mc = new ManagementClass("Win32_NetworkAdapterConfiguration");
    ManagementObjectCollection moc = mc.GetInstances();
    string MACAddress = String.Empty;
    foreach (ManagementObject mo in moc)
    {
        if (MACAddress == String.Empty)  // only return MAC Address from first card
        {
            if ((bool)mo["IPEnabled"] == true) MACAddress = mo["MacAddress"].ToString();
        }
        mo.Dispose();
    }

    MACAddress = MACAddress.Replace(":", "");
    return MACAddress;
}