diff --git a/trunk/ProcessHacker.Native/OSVersion.cs b/trunk/ProcessHacker.Native/OSVersion.cs
index fcd5159fb..14f83e652 100644
--- a/trunk/ProcessHacker.Native/OSVersion.cs
+++ b/trunk/ProcessHacker.Native/OSVersion.cs
@@ -33,6 +33,11 @@ namespace ProcessHacker.Native
 
     public enum WindowsVersion
     {
+        /// <summary>
+        /// Windows 2000.
+        /// </summary>
+        Win2000 = 50,
+
         /// <summary>
         /// Windows XP SP2, SP3.
         /// </summary>
@@ -56,7 +61,12 @@ namespace ProcessHacker.Native
         /// <summary>
         /// An unreleased version of Windows.
         /// </summary>
-        Unreleased = int.MaxValue
+        Unreleased = int.MaxValue,
+
+        /// <summary>
+        /// An unsupported version of Windows.
+        /// </summary>
+        Unsupported = int.MinValue
     }
 
     public static class OSVersion
@@ -83,16 +93,66 @@ namespace ProcessHacker.Native
         {
             System.Version version = Environment.OSVersion.Version;
 
-            if (version.Major == 5 && version.Minor == 1)
-                _windowsVersion = WindowsVersion.XP;
-            else if (version.Major == 5 && version.Minor == 2)
-                _windowsVersion = WindowsVersion.Server2003;
-            else if (version.Major == 6 && version.Minor == 0)
-                _windowsVersion = WindowsVersion.Vista;
-            else if (version.Major == 6 && version.Minor == 1)
-                _windowsVersion = WindowsVersion.Seven;
-            else if ((version.Major == 6 && version.Minor > 1) || version.Major > 6)
-                _windowsVersion = WindowsVersion.Unreleased;
+            switch (version.Major)
+            {
+                case 5:
+                    {
+                        switch (version.Minor)
+                        {
+                            case 0:
+                                _windowsVersion = WindowsVersion.Win2000;
+                                break;
+                            case 1:
+                                _windowsVersion = WindowsVersion.XP;
+                                break;
+                            case 2:
+                                _windowsVersion = WindowsVersion.Server2003;
+                                break;
+                            default:
+                                break; //Not detected, jump to version.Major default
+                        }
+                        break;
+                    }
+                case 6:
+                    {
+                        switch (version.Minor)
+                        {
+                            case 0:
+                                _windowsVersion = WindowsVersion.Vista;
+                                break;
+                            case 1:
+                                _windowsVersion = WindowsVersion.Seven;
+                                break;
+                            default:
+                                break; //Not detected, jump to version.Major default
+                        }
+                        break;
+                    }
+                default:
+                    if (version.Major > 6 || version.Minor > 1) //check if newer than latest Windows release
+                    {
+                        _windowsVersion = WindowsVersion.Unreleased;
+                        break;
+                    }
+                    else //OS version not detected and not newer than the newest Windows release
+                        _windowsVersion = WindowsVersion.Unsupported;
+                        break;
+            }
+
+            //if (version.Major == 5 && version.Minor == 0)
+            //    _windowsVersion = WindowsVersion.Win2000;
+            //else if (version.Major == 5 && version.Minor == 1)
+            //    _windowsVersion = WindowsVersion.XP;
+            //else if (version.Major == 5 && version.Minor == 2)
+            //    _windowsVersion = WindowsVersion.Server2003;
+            //else if (version.Major == 6 && version.Minor == 0)
+            //    _windowsVersion = WindowsVersion.Vista;
+            //else if (version.Major == 6 && version.Minor == 1)
+            //    _windowsVersion = WindowsVersion.Seven;
+            //else if ((version.Major == 6 && version.Minor > 1) || version.Major > 6)
+            //    _windowsVersion = WindowsVersion.Unreleased;
+            //else
+            //    _windowsVersion = WindowsVersion.Unsupported;
 
             if (IsBelow(WindowsVersion.Vista))
             {
diff --git a/trunk/ProcessHacker/Program/Program.cs b/trunk/ProcessHacker/Program/Program.cs
index 5f7d089a1..6c29b1bcc 100644
--- a/trunk/ProcessHacker/Program/Program.cs
+++ b/trunk/ProcessHacker/Program/Program.cs
@@ -119,11 +119,24 @@ namespace ProcessHacker
             Application.EnableVisualStyles();
             Application.SetCompatibleTextRenderingDefault(false);
 
-            if (Environment.Version.Major < 2)  
+            //before parsing commandline arguments, check OS support.
+            if (OSVersion.IsBelow(WindowsVersion.Win2000))
+            {
+                PhUtils.ShowError("This Operating System is not supported!");
+                Environment.Exit(1);
+            }
+            else if (OSVersion.WindowsVersion == WindowsVersion.Unreleased)
+            {
+                PhUtils.ShowError("This Operating System is unreleased and not currently supported," + 
+                    "\nProcess Hacker support has not been tested so expect bugs and issues.");
+            }
+
+            if (Environment.Version.Major < 2)
             {
                 PhUtils.ShowError("You must have .NET Framework 2.0 or higher to use Process Hacker.");
                 Environment.Exit(1);
             }
+
 #if !DEBUG            
             // Setup exception handling at first opportunity to catch exceptions generatable anywhere.
             Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException);