Cannot Close Down MS Word From .NET - vb.net

Question

I have the following snippet of code. It works (opens all the Word documents in a directory and then closes them down)...but it doesn't clean up after itself when I totally exit the program.
By this I mean that if I look at the TaskManager once I exit the VB.NET application I see the WINWORD.EXE even though it did not exist before I opened the application.
Here's the declarations I have:
Dim WordApp As Microsoft.Office.Interop.Word.Application
Dim aDoc As Microsoft.Office.Interop.Word.Document
Dim missing As Object = System.Reflection.Missing.Value
Dim nullobj As Object = System.Reflection.Missing.Value
Dim MYreadOnly As Object = False
Dim isVisible As Object = False
And here's the code:
Private Sub cmdGenerate_Click(sender As System.Object, e As System.EventArgs) Handles cmdGenerateKeywords.Click
Dim xmldoc As New XmlDataDocument()
Dim xmlnode As XmlNodeList
Dim i As Integer
Dim fs As FileStream
WordApp = New Microsoft.Office.Interop.Word.Application
WordApp.Visible = False
For Each f As FileInfo In New DirectoryInfo(txtFolderName.Text).GetFiles("*.docx")
' Open the document that was chosen by the dialog
aDoc = WordApp.Documents.Open(f.FullName, missing, [MYreadOnly], _
missing, missing, missing, missing, missing, missing, missing, _
missing, isVisible)
'aDoc.Close()
aDoc = Nothing
Next
'Close the Word Document
'aDoc.Close(nullobj, nullobj, nullobj)
WordApp.Application.Quit()
WordApp = Nothing
End Sub
As you can tell I've commented and uncommented various statements in regards to closing down Word documents and the Word Application itself. Nothing I have tried seems to be able to get rid of that pesky WINWORD.EXE
Something seems to have a lock and will not let it close down? Is that it?

Answer 1

Run explicitly Garbage Collector, as is shown in this article:
// Clean up the unmanaged Word COM resources by forcing a garbage
// collection as soon as the calling function is off the stack (at
// which point these objects are no longer rooted).
GC.Collect();
GC.WaitForPendingFinalizers();
// GC needs to be called twice in order to get the Finalizers called
// - the first time in, it simply makes a list of what is to be
// finalized, the second time in, it actually is finalizing. Only
// then will the object do its automatic ReleaseComObject.
GC.Collect();
GC.WaitForPendingFinalizers();
Despite link above, my experience is that run once is enough. But second call doesn't throw an error, so do it this way.

Answer 2

fs.Close()
fs.Dispose()
http://msdn.microsoft.com/en-us/library/system.io.filestream.dispose.aspx
This releases your resources. Might allow other close methods to work. I read through the code twice and do not see you using "fs" anywhere like I would expect.