Step 1: Include the 
following namespace
using 
System.Data.OleDb;
Step2: 
create the connection string 
string 
ConnStr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data 
Source=C:\Users\Pawan\Desktop\database.mdb;Jet OLEDB:Database Password=12345";
Step3: 
making a connection
OleDbConnection MyConn = 
new OleDbConnection(ConnStr);
MyConn.Open();
OleDbCommand Cmd = new
OleDbCommand(ConnStr, MyConn); 
Step4: reading the value 
from acces database 
         
Cmd.CommandText =
"Select * from UserInfo where UserName='"+textBox1.Text+"' 
and Password='"+textBox2.Text+"'";
OleDbDataReader ObjReader = Cmd.ExecuteReader();