var processStartInformation = new ProcessStartInfo
            {
                WorkingDirectory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), "sysnative"),
                FileName = "dism.exe",
                Arguments = @"/Online /Enable-Feature /FeatureName:NetFx3 /All",
                WindowStyle = ProcessWindowStyle.Hidden,
                UseShellExecute = true,
                Verb = "runas"
            };
            Process process = Process.Start(processStartInformation);
            process.WaitForExit();