Searching Directory Recrusivly For File Extensions

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VB

I have looked through more than 60 pages on the net to try and find the best method to search directories and sub-directories for specified file extensions. I have built an anti-virus but do not wish for it to scan every file type.
Where can I alter this code to allow multiple file extensions to be scanned only? and not every file?

Example:
.exe
.com
.sys

and so forth.

This code is the form of recursion that I am currently using.

Public Sub starting_scan()
            stop_Scan = False
            If Directory.Exists(myscanpath.Text) = True Then
                Scanning = True
                ScanScanner(txtScanningNow.Text)
            Else
                Timer1.Stop()
                MsgBox("The Selected Drive Or Device Is Not Ready Or Has No Scannable Content", MsgBoxStyle.Critical)
                SwitchButton4.Value = False
                Exit Sub
            End If
            Dim drives As String() = Directory.GetLogicalDrives()
            Dim aDrive As String
            For Each aDrive In drives
                myscanpath.Text = aDrive
                ScanScanner(txtScanningNow.Text)
            Next
            stop_Scan = True
            Timer1.Stop()
            Scanning = False
            txtScanningNow.Text = comboBox1.SelectedItem
            SwitchButton4.Value = False
            If lblvirus.Text = 0 Then
                DelVirusInfection.Enabled = False
            Else
                DelVirusInfection.Enabled = True
            End If
    End Sub
    
    Sub ScanScanner(ByVal dir As String)
        MD5Text.Text = MD5Reader.ReadToEnd
        Try
            With My.Computer.FileSystem
                If stop_Scan = True Then
                    Exit Sub
                End If
                For Each file1 In Directory.EnumerateFiles(dir)
                    Dim fs As New FileInfo(file1)
                    ComputerFileHash.Text = getMd5Hash(fs.FullName)
                    labelX13.Text = getSHA1Hash(fs.FullName)
                    If MD5Text.Text.Contains(ComputerFileHash.Text) Then
                        CheckedListBoxControl1.Items.Add(fs.FullName)
                        lblvirus.Text = CheckedListBoxControl1.Items.Count
                    End If
                    getmyfileatr(file1)
                    Dim fileDetail As IO.FileInfo
                    fileDetail = My.Computer.FileSystem.GetFileInfo(file1)
                    lblSizef.Text = fileDetail.Length
                    txtScanningNow.Text = file1
                Next file1
                ' Search child directories.
                For Each folder As Object In .GetDirectories(dir)
                    txtScanningNow.Text = folder
                    ScanScanner(folder)
                Next folder
            End With
        Catch ex As UnauthorizedAccessException
            Return
        End Try
    End Sub

How do I filter this?

Thank you in advance.