Try this code.
Option Explicit
Private Sub CommandButton1_Click() 'Previous
Dim n As Long
n = Me.ListBox1.ListCount - 1
Select Case Me.ListBox1.ListIndex
Case Is < 1
Me.ListBox1.ListIndex = n
Case Else
Me.ListBox1.ListIndex = Me.ListBox1.ListIndex - 1
End Select
End Sub
Private Sub CommandButton2_Click() 'Next
Dim n As Long
n = Me.ListBox1.ListCount - 1
Select Case Me.ListBox1.ListIndex
Case Is < n
Me.ListBox1.ListIndex = Me.ListBox1.ListIndex + 1
Case Else
Me.ListBox1.ListIndex = 0
End Select
End Sub
Private Sub CommandButton3_Click() 'Search
Dim Search As String
Dim n As Long
Dim i As Long
Dim j As Long
Search = Me.TextBox1.Text
n = Len(Me.TextBox1)
j = Me.ListBox1.ListCount - 1
For i = 0 To j
If Left(Me.ListBox1.List(i), n) = Search Then
Me.ListBox1.Selected(i) = True
Exit For
End If
Next
End Sub