[DllImport("Kernel32.dll")]
        public static extern void QueryPerformanceCounter(ref long ticks);

        private PerformanceCounter _AverageDuration;
        private PerformanceCounter _AverageDurationBase;
        private long tmr;
        private bool val = false;

        private void Form1_Load(object sender, EventArgs e)
        {
            bool performaceCounterCategoryExists = PerformanceCounterCategory.Exists("MyTestCategory");

            //if (performaceCounterCategoryExists)
            //{
            //    PerformanceCounterCategory.Delete("MyTestCategory");
            //    this.Close();
            //}
            

            if (!performaceCounterCategoryExists)
            {
                CounterCreationDataCollection counters = new CounterCreationDataCollection();

                CounterCreationData avgDuration = new CounterCreationData();
                avgDuration.CounterName = "average time per operation";
                avgDuration.CounterHelp = "Average duration per operation execution";
                avgDuration.CounterType = PerformanceCounterType.AverageTimer32;
                counters.Add(avgDuration);

                CounterCreationData avgDurationBase = new CounterCreationData();
                avgDurationBase.CounterName = "average time per operation base";
                avgDurationBase.CounterHelp = "Average duration per operation execution base";
                avgDurationBase.CounterType = PerformanceCounterType.AverageBase;
                counters.Add(avgDurationBase);


                // create new category with the counters above
                PerformanceCounterCategory.Create("MyTestCategory",
                            "Sample category for Codeproject", counters);
            }

            _AverageDuration = new PerformanceCounter();
            _AverageDuration.CategoryName = "MyTestCategory";
            _AverageDuration.CounterName = "average time per operation";
            _AverageDuration.MachineName = ".";
            _AverageDuration.ReadOnly = false;
            _AverageDuration.RawValue = 0;

            _AverageDurationBase = new PerformanceCounter();
            _AverageDurationBase.CategoryName = "MyTestCategory";
            _AverageDurationBase.CounterName = "average time per operation base";
            _AverageDurationBase.MachineName = ".";
            _AverageDurationBase.ReadOnly = false;
            _AverageDurationBase.RawValue = 0;

            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            long startTime = 0;
            long endTime = 0;

            QueryPerformanceCounter(ref startTime);

            val = !val;
            checkBox1.Checked = val;
            checkBox2.Checked = val;
            checkBox3.Checked = val;
            checkBox4.Checked = val;
            checkBox5.Checked = val;

            //System.Threading.Thread.Sleep(500);

            QueryPerformanceCounter(ref endTime);

            tmr = endTime - startTime;
            _AverageDuration.IncrementBy(tmr);
            label1.Text = string.Format("{0:0.0000}", tmr);
        }