A more .net style function for getting a window using an indexOf:

    ''API Imports
    <Runtime.InteropServices.DllImport("user32.dll", CharSet:=Runtime.InteropServices.CharSet.Auto)> Private Shared Sub GetClassName(ByVal hWnd As System.IntPtr, ByVal lpClassName As System.Text.StringBuilder, ByVal nMaxCount As Integer)
    End Sub
    <Runtime.InteropServices.DllImport("user32.dll", CharSet:=Runtime.InteropServices.CharSet.Auto)> Private Shared Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
    End Function

    ''FoundWindow stricture
    Public Structure FoundWindow
        Dim strWindowName As String
        Dim strClassName As String
        Dim hWnd As IntPtr
    End Structure

    ''' <summary>
    ''' This function is used to loop through all running processes, checking their main windows to see which ones contain a specific string
    ''' </summary>
    ''' <param name="strIndexOf">The string that you wish to check for in the window captions</param>
    ''' <param name="boolCase">Whether the function is should check for case</param>
    ''' <returns>A list of FoundWindow's containing the window name, class and handle</returns>
    ''' <remarks>As this function only loops through running processes main windows, it may miss some windows.</remarks>
    Public Function FindWindowsIndexOf(ByVal strIndexOf As String, ByVal boolCase As Boolean) As List(Of FoundWindow)
        Dim foundWindows As New List(Of FoundWindow)
        If boolCase = False Then
            strIndexOf = strIndexOf.ToLower
        End If
        For Each p As Process In Process.GetProcesses
            Dim windowCaption As String = p.MainWindowTitle
            If boolCase = False Then
                windowCaption = windowCaption.ToLower
            End If
            If windowCaption.IndexOf(strIndexOf) > -1 Then
                Dim foundWindow As New FoundWindow
                foundWindow.hWnd = FindWindow(vbNullString, p.MainWindowTitle)
                foundWindow.strWindowName = p.MainWindowTitle
                Dim sbClassName As New System.Text.StringBuilder("", 256)
                GetClassName(foundWindow.hWnd, sbClassName, 256)
                foundWindow.strClassName = sbClassName.ToString
                foundWindows.Add(foundWindow)
            End If
        Next
        Return foundWindows
    End Function

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each fWnd As FoundWindow In FindWindowsIndexOf("TeST", False)
            Debug.WriteLine(fWnd.strWindowName & " : " & fWnd.hWnd.ToString)
        Next
    End Sub

Same as the last function, you can choose whether or not the function is case sensitive.