Well, seeing as how you're not using any Databases, and I'm assuming that this is just for the Local Machine. I would suggest you using a Simple Stream Reader/Writer For, Reading and Writing to Files. These files could store your account Information (User/Pass) and can be encrypted using many encryption methods (That is, if you need the security level).

Here's some Sample Code to put you in the Right Direction:

Code:
If My.Computer.FileSystem.FileExists("C:\Accounts.txt") Then 'Checks to see if the file exists.
            Dim Input As New IO.StreamReader("C:\Accounts.txt") 'Create a new Stream Reader. This is used to read our file.
            MessageBox.Show("Contents: " & vbNewLine & Input.ReadToEnd, "File contents", MessageBoxButtons.OK, MessageBoxIcon.Information) 'Displays the contents of the file.
            Input.Close() 'Closes the Stream so it doesn't conflict with Windows. This is IMPORTANT!
        Else 'The file does not exist.
            Dim Output As New IO.StreamWriter("C:\Accounts.txt") 'Creates a new Stream/File for us to use.
            Output.WriteLine("Username: Admin") 'Writes a line to the Text file showing our Username.
            Output.WriteLine("Password: 4321") 'Writes another line to the Text file showing our Password.
            Output.Close() 'Closes the Stream so it doesn't conflict with Windows. This is IMPORTANT!
            MessageBox.Show("Sucessfully Created Account!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Information) 'Tells the User that the account has been created.
        End If