Program.cs

using System;
using System.IO;
using System.Diagnostics;
using System.Windows.Forms;

class Program
{
    [STAThread]
    static void Main()
    {
        string rbx = "Roblox";
        string exe = "RobloxStudioBeta.exe";
        string path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), rbx, "Versions");

        if (!Directory.Exists(path))
        {
            MessageBox.Show("An installation of Roblox does not exist for this user.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            return;
        }

        foreach (string dir in Directory.GetDirectories(path, "version-*"))
        {
            string exePath = Path.Combine(dir, exe);
            if (File.Exists(exePath))
            {
                Process.Start(exePath);
                return;
            }
        }

        MessageBox.Show("Did not find Roblox Studio in this user's Roblox installation.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        return;
    }
}