[virxen]

try the changes below

Option Explicit
  Dim conn As New ADODB.Connection
  Dim cmdCommand As New ADODB.Command
  Dim rec As New ADODB.Recordset
Private Function connect()
  conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & _
    App.Path & "\" & "db1.mdb;Mode=Read|Write"
  conn.CursorLocation = adUseClient
  conn.Open
      cmdCommand.ActiveConnection = conn
      cmdCommand.CommandType = adCmdText
      rec.CursorType = adOpenDynamic
      rec.CursorLocation = adUseClient
      rec.LockType = adLockOptimistic
End Function

Private Sub Form_Load()
connect
End Sub

Private Sub Command1_Click()
cmdCommand.CommandText = "SELECT * FROM table1;"
rec.Open cmdCommand
rec.AddNew
rec.Fields(1) = Text1.Text
rec.Fields(2) = Text2.Text
rec.Fields(3) = Text3.Text
rec.Fields(4) = Text4.Text
     rec.Update
     'If Not rec.EOF Then rec.MoveNext
     MsgBox "record stored"
     rec.Close

End Sub

Private Sub Form_Unload(Cancel As Integer)
conn.Close
End Sub

Private Sub Text2_Click()
Form1.Text2.Text = Val(Form1.Text1.Text) * 1#
End Sub

Private Sub Text3_Click()
Form1.Text3.Text = Val(Form1.Text1.Text)
End Sub
Private Sub Text4_Click()
Form1.Text4.Text = Val(Form1.Text2.Text)
End Sub