wtf?

if (sw ==null)
{
    sw = new Stopwatch();
    ResetStopwatch();
}

// Was the following: the purpose was: check if there is a stopwatch, if not, do the create one and reset it.
// the code above seems simpeler

//try
//{
//    bool check = sw.IsRunning;
//}
//catch
//{
//    sw = new Stopwatch();
//    ResetStopwatch();
//}