C# newbie question on a variable

I understand PowerShell but this is my first ever attempt at C# using Visual studio 2013.
I want to be able to click one of my programs, get a description of it and then choose to run it.
So far I have most of what I want but I am stuck on the variable portion.
I think the issue is the variable does not carry into the next code block for lack of a better understanding.
Hope the picture is shown.


I click FindTST radio button and I get my description of what it does in the text box. That part works fine.
After I see what it I want to click run it and have it start the program.
So I have stored it in a variable called path1 but the button that says RunIT does not seem to recognize the variable path1.
My code is below.
Thanks

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication8
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {

        }

        private void checkBox2_CheckedChanged(object sender, EventArgs e)
        {

        }

        private void RBFindTST_CheckedChanged(object sender, EventArgs e)
        {
            
            string  path1 = @"C:\Users\9201401145\Google Drive\Scripts\PowerShell\FIND THE TST.exe";
            
            TXTInfo.Text = "Runs the below program." + "\r\n\r\n" + " " + path1;
            // C:\Users\9201401145\Google Drive\Scripts\PowerShell\FIND THE TST.exe
            

        }

        private void TXTInfo_TextChanged(object sender, EventArgs e)
        {
            
        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)
        {
            TXTInfo.Text = "";
        }

        private void BTNRunIT_Click(object sender, EventArgs e)
        {
            TXTInfo.Text = path1;

        }
    }
}

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