.net installed programs

gistfile1.cs

                    if (Request.ContentType == Common.ContentTypeAsXml)
                    {
                        //Rails logic:
                        //mark all programs for this machine to installed=false
                        //then for each program if exists mark installed as true 
                        //else add


                        var installedProgramsXML = new StreamReader(Request.InputStream).ReadToEnd();
                        var installedPrograms = Utils.DeserializeObjects(installedProgramsXML, typeof(InstalledProgram[]));

                        //if they are more than one installed program
                        if (installedPrograms.Count() >= 1)
                        {
                            //get the first installed program from the list
                            var firstInstalledProgram = installedPrograms[0] as InstalledProgram;
                            //if the installed program is not null
                            if (firstInstalledProgram != null)
                            {
                                //use the machine id from the first installed program. the same machine id should be the same for all the installed programs
                                var machineId = firstInstalledProgram.MachineId;

                                //var installedProgramsForMachine = from p in db.InstalledPrograms
                                //                                  where p.MachineId == machineId
                                //                                  select p;

                                //recive the machine from db
                                Machine machine = db.Machines.Find(machineId);

                                //for each installed program on this machine
                                foreach(var existingInstalledProgram in machine.InstalledPrograms.ToList())
                                {
                                    //mark Installed property as false
                                    existingInstalledProgram.Installed = false;
                                }

                                //for each installed program sended for this machine
                                foreach (var installedProgram in installedPrograms)
                                {

                                    //search for installedProgram if allready is in the db 
                                    var duplicateInstalledPrograms =
                                        machine.InstalledPrograms.ToList().Where(
                                            p => p.DisplayName == (installedProgram as InstalledProgram).DisplayName && p.Version==(installedProgram as InstalledProgram).Version);

                                    //if the installed program allready exist in the db one time or more
                                    if (duplicateInstalledPrograms.Count() >= 1)
                                    {
                                        //new instance of installed program
                                        InstalledProgram duplicateInstalledProgram = new InstalledProgram();
                                        //get the last installed program from duplicateInstalledPrograms
                                        duplicateInstalledProgram = duplicateInstalledPrograms.Last();
                                        //mark it as installed
                                        duplicateInstalledProgram.Installed = true;
                                        //add it to the db
                                        db.InstalledPrograms.Add(duplicateInstalledProgram);

                                        //remove all the duplicates from db
                                        foreach (var program in duplicateInstalledPrograms)
                                        {
                                            db.InstalledPrograms.Remove(program);
                                        }
                                    }
                                        //if is not in the db
                                    else
                                    {
                                        //add the installed program to the db
                                        db.InstalledPrograms.Add((InstalledProgram)installedProgram);
                                    }
                                    
                                }

                                //and save changes to db
                                db.SaveChanges();
                            }
                        }


                        return this.Content("<result>success</result>");
                    }