connect with access using c# errors

I HAVE THIS ERRORS WHEN I TRY TO RUN MY CODE in visual studio 2012:
When i press save button:
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1. An unhandled exception of type 'System.InvalidOperationException' occurred in System.Data.dll
   Additional information: ExecuteReader requires an open and available Connection. The connection's current state is closed.

When i press show all button:
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2. An unhandled exception of type 'System.InvalidOperationException' occurred in System.Data.dll

Additional information: The 'Microsoft.ACE.OLEBD.12.0' provider is not registered on the local machine.

The code i run:

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;
using System.Data.OleDb;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        
        
        OleDbConnection vcon=new OleDbConnection(@"Provider=Microsoft.ACE.OLEBD.12.0; Data source=C:\Users\user\Desktop\DBMS.accdb");
       

        public Form1()
        {
            InitializeComponent();
           
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            vcon.Open();
        
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            string vsql = string.Format("insert into PartA values ((0),(1),(2),(3),(4))",textBox1.Text,int.Parse(textBox2.Text),textBox3.Text,textBox4.Text,textBox5.Text);
            
OleDbCommand vcom = new OleDbCommand(vsql, vcon);

            vcom.ExecuteReader();
            MessageBox.Show("Data stored succesfully");
            vcom.Dispose();

        
        }
        private void button4_Click(object sender, EventArgs e)
        {
            string vsql = "Select * from partA ";
            OleDbCommand vcom = new OleDbCommand(vsql, vcon);
            DataSet vds = new DataSet();
            OleDbDataAdapter vda = new OleDbDataAdapter(vcom);
            vda.Fill(vds, "res");
            dataGridView1.DataSource = vds.Tables["res"];
            vda.Dispose();
            vcom.Dispose();


        }

      
What is the solution about this error??