opening an external .exe file from a game

hi. im trying to make a launcher for all of my games because i have alot of them. i have tried to use this code:

#pragma strict

function OnMouseDown ()
{
System.Diagnostics.Process.Start(Application.dataPath + "Desktop");
 //or directly to open external programs:
 System.Diagnostics.Process.Start("RacingPlanet2Launch.exe");
}

but it doesnt work. please could somebody help me fix it? the error i get with it is:

Win32Exception: The system cannot find the file specified.

System.Diagnostics.Process.Start_shell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
System.Diagnostics.Process.Start_common (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
System.Diagnostics.Process.Start (System.Diagnostics.ProcessStartInfo startInfo)
System.Diagnostics.Process.Start (System.String fileName)
Open Racing Planet 2.OnMouseDown () (at Assets/Open Racing Planet 2.js:5)
UnityEngine.SendMouseEvents:DoSendMouseEvents(Int32, Int32)

The issue is exactly as it says, it can not find the application you wish to open.

if RacingPlanet2Launch.exe is in the same directory as the launcher the bottom line should work.

the error is coming from the line above where you open nothing, it seems you are trying to browse to your desktop which is incorrect. Remove that line completely.

function OnMouseDown ()
{
//will open if exe is in same directory as launchers exe file.
System.Diagnostics.Process.Start("RacingPlanet2Launch.exe");

//Logs the dataPath so you can see where your applications should be
Debug.Log(Application.dataPath);

//will open from the applications dataPath directory
System.Diagnostics.Process.Start(Application.dataPath + "/RacingPlanet2Launch.exe");
}