diff --git a/src/Nav.java b/src/Nav.java
index 8bbede3..da0a414 100644
--- a/src/Nav.java
+++ b/src/Nav.java
@@ -3,10 +3,11 @@ import java.io.File;
 import java.io.FileNotFoundException;
 
 import javax.swing.JPanel;
-import javax.swing.JComboBox;
 import javax.swing.JLabel;
 import javax.swing.JButton;
 
+import gui.ComboBox;
+import gui.FileChooser;
 /**
  * The Nav class represents the Navigation bar at the top of the JFrame window.
  *
@@ -85,26 +86,52 @@ public class Nav extends JPanel {
      * debugging purposes.
      */
     private void createGUI() {
-        JComboBox<String> fileOptions = new JComboBox<String>();
-            fileOptions.addItem("New");
-            fileOptions.addItem("Open");
-            fileOptions.addItem("Save");
-            fileOptions.addItem("Exit");
-            
         JLabel elapsedTime = new JLabel("Elapsed Time: 00:00:00");
-
         JButton solve = new JButton("Solve");
 
-        add(fileOptions);
+        add(createFileOptions());
         add(elapsedTime);
         add(solve);
     }
 
+    /**
+     * Create the ComboBox for the file options.
+     * 
+     * @return ComboBox<String>
+     */
+    private ComboBox<String> createFileOptions() {
+        ComboBox<String> fileOptions = new ComboBox<>();
+            fileOptions.addItem("New");
+            fileOptions.addItem("Open");
+            fileOptions.addItem("Save");
+            fileOptions.addItem("Exit");
+
+        fileOptions.addActionListener(e -> {
+            String selected = (String) fileOptions.getSelectedItem();
+            switch(selected) {
+                case "New":
+                    newFile();
+                    break;
+                case "Open":
+                    openFile();
+                    break;
+                case "Save":
+                    saveFile();
+                    break;
+                case "Exit":
+                    System.exit(0);
+                    break;
+                default:
+                    System.out.println("Invalid selection.");
+            }
+        });
+
+        return fileOptions;
+    }
+
     /**
      * Given the user's selection from the JComboBox, perform the appropriate
      * action.
-     *
-     * @param String
      */
     private void newFile() {
         int defaultOption = s.getNewFileProperties();
@@ -120,8 +147,30 @@ public class Nav extends JPanel {
         // TODO: Create a new .sdku file in the default directory.
     }
 
+    /**
+     * Open an existing .sdku file in the user's file system, using a GUI.
+     */
+    private void openFile() {
+        File defaultDirectory = new File(s.getDefaultDirectory());
+        if(defaultDirectory != null || !defaultDirectory.isDirectory()) {
+            defaultDirectory.mkdirs();
+        }
+
+        FileChooser fc = new FileChooser(defaultDirectory);
+        int result = fc.showOpenDialog(this);
+
+        if(result == FileChooser.APPROVE_OPTION) {
+            f = fc.getSelectedFile();
+            createGrid(f);
+        } else {
+            System.out.println("No file was selected.");
+        }
+    }
+
     /**
      * Given an input filename, open the file and populate the grid.
+     * 
+     * This implementation is for use only in the command-line interface. 
      *
      * @param String
      */
@@ -140,6 +189,7 @@ public class Nav extends JPanel {
             return;
         }
 
+        System.out.println("Opening the file " + filename + ".sdku.");
         createGrid(f);
     }
 
diff --git a/src/Settings.java b/src/Settings.java
index 4490228..fcefba6 100644
--- a/src/Settings.java
+++ b/src/Settings.java
@@ -1,3 +1,4 @@
+
 import java.util.Scanner;
 import java.io.File;
 
@@ -20,7 +21,7 @@ public class Settings {
         // settings, effectively toggles. If the file does not exist,
         // populate it with the following values (possibly in .json).
         newFileProperties = 0;
-        defaultDirectory = "~/AppData/Local/sudoku/";
+        defaultDirectory = "C:\\Users\\jashton\\AppData\\Local\\Sudoku"; // TODO: This is a Windows default. Need OS detection.
     }
 
     /**
diff --git a/src/gui/ComboBox.java b/src/gui/ComboBox.java
new file mode 100644
index 0000000..95e8c0d
--- /dev/null
+++ b/src/gui/ComboBox.java
@@ -0,0 +1,25 @@
+package gui;
+
+import javax.swing.JComboBox;
+
+/**
+ * A custom JComboBox with the appropriate styling for the Sudoku app.
+ */
+public class ComboBox<E> extends JComboBox<E> {
+    
+    /**
+     * Create a new ComboBox with the default styling and without initial items.
+     */
+    public ComboBox() {
+        super();
+        style();
+    }
+
+    /**
+     * Set up the ComboBox with the appropriate styling.
+     */
+    private void style() {
+        // TODO: Style the ComboBox.
+        System.out.println("TODO: Style the ComboBox.");
+    }
+}
diff --git a/src/gui/FileChooser.java b/src/gui/FileChooser.java
new file mode 100644
index 0000000..7066527
--- /dev/null
+++ b/src/gui/FileChooser.java
@@ -0,0 +1,62 @@
+package gui;
+
+import java.io.File;
+import javax.swing.filechooser.FileFilter;
+import javax.swing.JFileChooser;
+
+/**
+ * A custom FileChooser with the appropriate styling for the Sudoku app.
+ * Additionally, this FileChooser only allows .sdku files to be selected.
+ */
+public class FileChooser extends JFileChooser {
+    
+    /**
+     * Create a new FileChooser with the default directory set to the user's
+     * Sudoku directory.
+     * 
+     * @param defaultDirectory
+     */
+    public FileChooser(File defaultDirectory) {
+        super(defaultDirectory);
+        for (File f: defaultDirectory.listFiles()) {
+            ensureFileIsVisible(f);
+        }
+        style();
+        setupSettings();
+    }
+
+    /**
+     * Set up the FileChooser with the appropriate styling.
+     */
+    private void style() {
+        // TODO: Style the FileChooser.
+        System.out.println("TODO: Style the FileChooser.");
+    }
+
+    /**
+     * Set up the FileChooser with the appropriate settings.
+     */
+    private void setupSettings() {
+        setFileHidingEnabled(false);
+        setFileSelectionMode(JFileChooser.FILES_ONLY);
+        rescanCurrentDirectory();
+        setFileFilter(new Filter());
+    }
+
+    /**
+     * A custom FileFilter to only allow .sdku files to be selected.
+     */
+    private class Filter extends FileFilter {
+        public boolean accept(File f) {
+            String name = f.getName().toLowerCase();
+            if(name.length() > 5) {
+                return name.substring(name.length() - 5).equals(".sdku") || !f.isDirectory();
+            }
+            return false;
+        }
+
+        public String getDescription() {
+            return "Sudoku Puzzle Files (*.sdku)";
+        }
+    }
+}
diff --git a/src/run.ps1 b/src/run.ps1
index 28ea8b4..9ef6518 100644
--- a/src/run.ps1
+++ b/src/run.ps1
@@ -5,6 +5,7 @@ function Run {
     javac *.java
     java App $flag
     rm *.class
+    rm gui/*.class
 }
 
 if ($args.Length -eq 1) {