How to programmatically launch an application under a specific user

ProcessStartInfo psi = new ProcessStartInfo("cmd", @"/C c:\SomeApp.exe");
psi.UserName = "UserName";
psi.Domain = "DomaiName";
psi.Password = ReadPassword("password");
psi.UseShellExecute = false;
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
psi.RedirectStandardError = true;
using (Process p = Process.Start(psi))
{  
  // if you need to wait the end of the process
  p.WaitForExit();
}

public System.Security.SecureString ReadPassword(string password)
{
 System.Security.SecureString secPass = new System.Security.SecureString();
 for (int i = 0; i < password.Length; i++)
  secPass.AppendChar(password[i]);
 return secPass;
}