string[] argv = Environment.GetCommandLineArgs(); string FileToUse = String.Empty; string Potential = String.Empty; string StartupPath = argv[0]; StartupPath = StartupPath.Substring(0, StartupPath.LastIndexOf('\\') + 1); Potential = StartupPath + "default.vp1"; if (File.Exists(Potential)) { FileToUse = Potential; } if (argv.Length == 2) { if (File.Exists(argv[1])) { FileToUse = argv[1]; } else if (Directory.Exists(argv[1])) { Potential = String.Format("{0}{1}{2}", argv[1], argv[1][argv[1].Length-1] == '\\'? String.Empty: "\\", "default.vp1"); if (File.Exists(Potential)) { FileToUse = Potential; } } } if (FileToUse.Length == 0) { // uh oh }