How to make sure that when clicking on the button5 button, the window that should open does not open due to an error?

Question

C++ / C#

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 Генератор
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
            this.FormBorderStyle = FormBorderStyle.None;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

        private void linkLabel2_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            Application.Exit();
        }

        private void linkLabel1_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            this.Hide();
            Form2 f = new Form2();
            if (f.ShowDialog() == DialogResult.OK)
            f.Show();
        }

        private void button5_Click(object sender, EventArgs e)
        {
            textBox1.Text = clearWord(textBox1.Text);
            textBox2.Text = clearWord(textBox2.Text);

            if ((checkBox1.Checked = false) && (checkBox2.Checked = false) && (checkBox3.Checked = false))
            {
                MessageBox.Show("Выберите уровень для вашего будущего домена", "Ошибка",
                MessageBoxButtons.OK);
            }

            List<string> keyWords = new List<string>();
            if (textBox1.Text != "") keyWords.Add(textBox1.Text);
            if (textBox2.Text != "") keyWords.Add(textBox2.Text);

            List<string> domainZoneEn = new List<string>();
            if (checkBox1.Checked)
                domainZoneEn.Add("ru");
            if (checkBox2.Checked)
                domainZoneEn.Add("su");
            List<string> domainZoneRu = new List<string>();
            if (checkBox3.Checked)
                domainZoneRu.Add("рф");

            this.Hide();
            Form7 f = new Form7(keyWords, domainZoneEn, domainZoneRu);
            if (f.ShowDialog() == DialogResult.OK)
            f.Show();
        }

        private string clearWord(string word)
        {
            return String.Join("", word.Split('@', ',', '.', ';', '\'', '\"', ' ', '-', '_', '#', '$', '!', '%', '^', '(', ')', '{', '}', '[', ']', '\\'));
        }

        private void button7_Click(object sender, EventArgs e)
        {
            this.Hide();
            Form2 f = new Form2();
            if (f.ShowDialog() == DialogResult.OK)
            f.Show();
        }

        private void button6_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}

Answer 1

What error are you talking about?
Wrap the code inside button5_Click in a try/catch.