We can always start a process in two different ways; without command-line argument and with command-line arguments. In order to start process you need to call Start method of the Process class.
ProcessStartInfo Info = new ProcessStartInfo();
Info.FileName = this.tbProcessName.Text;
Process.Start(Info);

OR

ProcessStartInfo Info = new ProcessStartInfo();
String MyFileName = @"C:\ProcessDemo.exe";
Process.Start(MyFileName);

If we want to start process with Arguments we’ll do it this way
ProcessStartInfo MyInfo = new ProcessStartInfo();
MyInfo.FileName = this.tbProcessName.Text;
MyInfo.Arguments = "LIST OF ARGUMENT";
Process.Start(MyInfo);

If we need to use Login and Password we’ll use this code
SecureString SecurePassword = new SecureString();
for (Int32 i = 0; i < this.tbPassword.Text.Length; i++)
{
        SecurePassword.AppendChar(Convert.ToChar(this.tbPassword.Text[i]));
}
Process.Start(this.tbUserName.Text, this.tbPassword.Text, SecurePassword, this.tbDomain.Text);

Each process has unique identifier that is used to determine each individual process.

Another good example of starting up a process is:
Process.Start("iexplore.exe", "http://www.microsoft.com");