How to start and use existing application (explorer)

List<int32> list = new List<int32>(); //list which will have identifiers of processes that you've started
...
...
//starting a new process
Process[] procs = Process.GetProcessesByName("explorer"); //get all explorers
foreach (Process p in procs)
{
    int baseAdd = p.MainModule.BaseAddress.ToInt32();
    if(list.Contains(baseAdd))
       p.Kill(); //kill previous process
}
var r = Process.Start("explorer.exe", argument);
list.Add(r.MainModule.BaseAddress.ToInt32); //store process started by you
</int32></int32>

Process m = new Process();
m.EnableRaisingEvents = true;
m.Exited += new EventHandler(this.MProcess_Exited);
m.StartInfo.FileName = "explorer.exe";
m.StartInfo.Arguments = "select," + e.Uri.LocalPath;
m.Start();

// When process stops, MProcess_Exited is called.
void MProcess_Exited(object sender, EventArgs e)
{
 // Do logic ?
}