Handling Accented Characters in a Write to File

I am newbie and am receiving a text file in Spanish that includes some characters with accents over them.  Then I read that text file into an array, massage it and write it back out to a text file.  However, the problem is that when I write it back out, the character with accents over them turn into nonsense characters.  Everything else seems to work.
Below is my code.  Does anyone have a solution?
Dim lines() As String = IO.File.ReadAllLines("c:\trans\test\testfile.txt")
Dim lineArray As New ArrayList() For x As Integer = 0 To lines.GetUpperBound(0) lineArray.Add(lines(x)) Next 'Dim num As String 'For Each num In lines TextBox1.Text = lineArray.Count 'if you have an ArrayList named lineArray Dim str() As String = lineArray.ToArray(GetType(String)) TextBox1.Text = TextBox1.Text & vbCrLf & str.Length & vbCrLf For I = 0 To str.Length - 1 str(I) = str ...