Trouble Renaming File with Textbox input

[RCA20]

I have been struggling a bit trying to get this to work. I am trying to rename the file but can't seem to get it to work. The file creates but just doesn't seem to rename with the text in the text box. Any ideas to point me in the right direction would be great. Below is the code.

Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click
 
        If File.Exists("c:\Sample.txt") Then
            'shows message if testFile exist
            MsgBox("File Already Exist ")
        Else
            'create the file testFile.txt
            File.Create("c:\Sample.txt")
            MsgBox("File Has Been Created ")
        End If
    End Sub

Public Sub RenameFile()
 
        Dim mOldFilePath As String = "C:\Sample.txt"
        'Dim mExtension As String
        Dim mNewFileName As String
        mNewFileName = txtName.Text
 
 
        My.Computer.FileSystem.RenameFile(mOldFilePath, mNewFileName)

Thanks in Advance

RCA20