System.Management

Just move my project made C#  .Net 2.0 by VS2005 and CSC  to SharpDevelop 5 .Net4.5

using System.Management; in list, as for C#  .Net 2.0 but mistake reference to

ManagementObjectSearcher objects = new ManagementObjectSearcher("SELECT * FROM Win32_PhysicalMemory");

Probably the question in System.Management.dll for .Net4.5

Because if I use System.Management.dll open from .Net 2.0, no mistake indicated just no function in

if  (System.Environment.Version.ToString().Trim().Equals("XXXXXXXXXXXX"))

Question: wich way update .Net4.5 System.Management.dll for functions of System.Environment , the best for motherboardID )))