Little help?

[Nean]

I started learning C# tonight, and I like to think that I'm alright for my first time, I still can't get my app to work. Basically it's just an app that I'll use to learn, I had originally written it in VB6, and now to learn the ropes I was remaking it in C#. The problem is, I need it to make sure the timer isn't activated if the interval is left blank, or the other textbox is left blank. It works for the interval, if the interval is empty it won't run, if the interval is filled and the other textbox is empty, it starts to run, however. Here's my code.

(I think it's probably something to do with the { } blocks, because I'm still not sure how to use them 100%)

Heres my code so far

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

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void timer1_Tick(object sender, EventArgs e)
        {
            SendKeys.Send(textBox1.Text);
            SendKeys.Send("{enter}");
        }

        private void button1_Click(object sender, EventArgs e)
        {

            if (textBox1.Text.Length.Equals(0))
            {
                MessageBox.Show("Enter a string to spam!", "Error");
                timer1.Enabled = false;
            }
            else
                timer1.Enabled = true;
        
                if (textBox2.Text.Length.Equals(0))
                {
                    MessageBox.Show("Enter an interval!", "Error");
                    timer1.Enabled = false;
                }
            
                else
                    timer1.Enabled = true;
            
        }
        

        private void button2_Click(object sender, EventArgs e)
        {
            timer1.Enabled = false;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void timer1_Tick_1(object sender, EventArgs e)
        {
            SendKeys.Send(textBox1.Text);
            SendKeys.Send("{enter}");
        }

        private void button1_Click_1(object sender, EventArgs e)
        {
            if (textBox1.Text.Length.Equals(0))
            {
                MessageBox.Show("Enter a string to spam!", "Error");
                timer1.Enabled = false;
            }
            else
                timer1.Enabled = true;
            
            if (textBox2.Text.Length.Equals(0))
            {
                MessageBox.Show("Enter an interval!", "Error");
                timer1.Enabled = false;
            }
        
            else
            
                timer1.Enabled = true;
            
        }

        private void button2_Click_1(object sender, EventArgs e)
        {
            timer1.Enabled = false;
        }   
        
    }
}