diff --git a/pppc.cc b/pppc.cc
index 46b1ce2..71ceddb 100644
--- a/pppc.cc
+++ b/pppc.cc
@@ -76,9 +76,13 @@ int WinMain(
         cerr << "Warning: Shell_NotifyIcon(): " << GetLastError() << endl;
     }
 
+    /* begin capturing session notifications */
+    session_notification_enable(hWnd);
+
     BOOL bRet;
     MSG msg;
-    for (;;)
+    bool running = true;
+    while(running)
     {
         bRet = GetMessage(&msg, NULL, 0, 0);
         if (bRet == -1 || bRet == 0)
@@ -93,21 +97,48 @@ int WinMain(
             case WM_COMMAND:
                 cerr << "WM_COMMAND" << endl;
                 break;
+            case WM_CLOSE:
+            case WM_DESTROY:
+            case WM_QUIT:
+                running = false;
+                break;
+            case WM_WTSSESSION_CHANGE:
+                if (msg.wParam == WTS_SESSION_LOGON
+                 || msg.wParam == WTS_SESSION_UNLOCK)
+                {
+                    pport_write(0xFF);
+                }
+                if (msg.wParam == WTS_SESSION_LOGOFF
+                 || msg.wParam == WTS_SESSION_LOCK)
+                {
+                    pport_write(0x0);
+                }
+                break;
         }
     }
 
+    /* stop listening for session notifications */
+    session_notification_disable(hWnd);
+
     return bRet;
 }
 
 LRESULT WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
-    cerr << "WindowProc()" << endl;
     switch (message)
     {
         case WM_NCCREATE:
             return 1;
         case WM_CREATE:
-            cerr << "WindowProc(): WM_CREATE" << endl;
+            break;
+        case WM_CLOSE:
+            DestroyWindow(hWnd);
+            break;
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            break;
+        case WM_ICON_NOTIFY:
+            cerr << "WM_ICON_NOTIFY" << endl;
             break;
     }
     return 0;