diff --git a/src/GregsStack.InputSimulatorStandard/InputBuilder.cs b/src/GregsStack.InputSimulatorStandard/InputBuilder.cs
index 147c0c9..7a9fe66 100644
--- a/src/GregsStack.InputSimulatorStandard/InputBuilder.cs
+++ b/src/GregsStack.InputSimulatorStandard/InputBuilder.cs
@@ -99,6 +99,7 @@ public InputBuilder()
         /// <returns>This <see cref="InputBuilder"/> instance.</returns>
         public InputBuilder AddKeyDown(VirtualKeyCode keyCode)
         {
+            var code = (ushort)((int)keyCode & 0xFFFF);
             var down =
                 new Input
                 {
@@ -108,8 +109,8 @@ public InputBuilder AddKeyDown(VirtualKeyCode keyCode)
                                 Keyboard =
                                     new KeyboardInput
                                         {
-                                            KeyCode = (ushort) keyCode,
-                                            Scan = (ushort)(NativeMethods.MapVirtualKey((uint)keyCode, 0) & 0xFFU),
+                                            KeyCode = (ushort) code ,
+                                            Scan = (ushort)(NativeMethods.MapVirtualKey((uint)code, 0) & 0xFFU),
                                             Flags = IsExtendedKey(keyCode) ? (uint) KeyboardFlag.ExtendedKey : 0,
                                             Time = 0,
                                             ExtraInfo = IntPtr.Zero
diff --git a/src/GregsStack.InputSimulatorStandard/Native/VirtualKeyCode.cs b/src/GregsStack.InputSimulatorStandard/Native/VirtualKeyCode.cs
index f2f78ec..e6b56d1 100644
--- a/src/GregsStack.InputSimulatorStandard/Native/VirtualKeyCode.cs
+++ b/src/GregsStack.InputSimulatorStandard/Native/VirtualKeyCode.cs
@@ -62,7 +62,7 @@ public enum VirtualKeyCode
         /// <summary>
         /// Numeric keypad ENTER key
         /// </summary>
-        NUMPAD_RETURN = 0x0D,
+        NUMPAD_RETURN = 0x4000000D,
 
         // 0x0E - 0x0F : Undefined
 
@@ -940,5 +940,7 @@ public enum VirtualKeyCode
         /// Clear key
         /// </summary>
         OEM_CLEAR = 0xFE,
+
+
     }
 }