public static int GetOSBit()
        {
            
            try
            {
                string addressWidth = String.Empty;
                ConnectionOptions mConnOption = new ConnectionOptions();
                ManagementScope mMs = new ManagementScope(@"\\localhost", mConnOption);
                ObjectQuery mQuery = new ObjectQuery("select AddressWidth from Win32_Processor");
                ManagementObjectSearcher mSearcher = new ManagementObjectSearcher(mMs, mQuery);
                ManagementObjectCollection mObjectCollection = mSearcher.Get();
                foreach (ManagementObject mObject in mObjectCollection)
                {
                    addressWidth = mObject["AddressWidth"].ToString();
                }
                return Int32.Parse(addressWidth);
            }
            catch (Exception ex)
            {
                return 32;
            }

需要引用System.Management，该方法在以Guest用户登录的情况下抛出异常：


或者用以下方法

[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)] 
[return: MarshalAs(UnmanagedType.Bool)] 
public static extern bool IsWow64Process([In] IntPtr hProcess, [Out] out bool lpSystemInfo); 


private static bool Is64Bit() 

{

bool retVal; 

IsWow64Process( Process.GetCurrentProcess().Handle, out retVal); 

return retVal; 

}

需要引用System.Diagnostics

参考http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/24792cdc-2d8e-454b-9c68-31a19892ca53/