Stores and accesses user preferences between sessions. Based off of Unity's PlayerPrefs class: http://docs.unity3d.com/ScriptReference/PlayerPrefs.html

UserPrefs.cs

using System;
using System.Reflection;
using Microsoft.Win32;

/// <summary>
/// Stores and accesses user preferences between sessions.
/// </summary>
public static class UserPrefs
{
    private static readonly RegistryKey MainKey;

    static UserPrefs()
    {
        MainKey =
            Registry.CurrentUser.CreateSubKey(string.Format("Software\\{0}\\{1}",
                GetAttribute<AssemblyCompanyAttribute>().Company, GetAttribute<AssemblyProductAttribute>().Product));
    }

    private static T GetAttribute<T>() where T : Attribute
    {
        return (T) Attribute.GetCustomAttribute(Assembly.GetEntryAssembly(), typeof (T), false);
    }

    /// <summary>
    /// Removes all keys and values from the preferences. Use with caution.
    /// </summary>
    public static void DeleteAll()
    {
        Array.ForEach(MainKey.GetValueNames(), s => MainKey.DeleteValue(s, false));
    }

    /// <summary>
    /// Removes key and its corresponding value from the preferences.
    /// </summary>
    public static void DeleteKey(string key)
    {
        MainKey.DeleteValue(string.Concat("f_", key), false);
        MainKey.DeleteValue(string.Concat("i_", key), false);
        MainKey.DeleteValue(string.Concat("s_", key), false);
    }

    /// <summary>
    /// Returns the value corresponding to key if it exists. If it doesn't exist, it will return defaultValue.
    /// </summary>
    public static float GetFloat(string key, float defaultValue)
    {
        return Convert.ToSingle(MainKey.GetValue(string.Concat("f_", key), defaultValue));
    }

    /// <summary>
    /// Returns the value corresponding to key if it exists. If it doesn't exist, it will return defaultValue.
    /// </summary>
    public static int GetInt(string key, int defaultValue)
    {
        return (int) MainKey.GetValue(string.Concat("i_", key), defaultValue);
    }

    /// <summary>
    /// Returns the value corresponding to key if it exists. If it doesn't exist, it will return defaultValue.
    /// </summary>
    public static string GetString(string key, string defaultValue)
    {
        return (string) MainKey.GetValue(string.Concat("s_", key), defaultValue);
    }

    /// <summary>
    /// Returns true if key exists in the preferences.
    /// </summary>
    public static bool HasKey(string key)
    {
        return (MainKey.GetValue(key, null) != null);
    }

    /// <summary>
    /// Sets the value of the preference identified by key.
    /// </summary>
    public static void SetFloat(string key, float value)
    {
        MainKey.SetValue(string.Concat("f_", key), value);
    }

    /// <summary>
    /// Sets the value of the preference identified by key.
    /// </summary>
    public static void SetInt(string key, int value)
    {
        MainKey.SetValue(string.Concat("i_", key), value);
    }

    /// <summary>
    /// Sets the value of the preference identified by key.
    /// </summary>
    public static void SetString(string key, string value)
    {
        MainKey.SetValue(string.Concat("s_", key), value);
    }
}