diff --git a/include/wx/msw/private.h b/include/wx/msw/private.h
index 3c48d8c7b1..f0c71a455e 100644
--- a/include/wx/msw/private.h
+++ b/include/wx/msw/private.h
@@ -280,12 +280,18 @@ extern HBITMAP wxInvertMask(HBITMAP hbmpMask, int w = 0, int h = 0);
 // get the current state of SHIFT/CTRL keys
 inline bool wxIsShiftDown()
 {
-    return (::GetKeyState(VK_SHIFT) & 0x100) != 0;
+//    return (::GetKeyState(VK_SHIFT) & 0x100) != 0;
+    // Returns different negative values on WinME and WinNT,
+    // so simply test for negative value.
+    return ::GetKeyState(VK_SHIFT) < 0;
 }
 
 inline bool wxIsCtrlDown()
 {
-    return (::GetKeyState(VK_CONTROL) & 0x100) != 0;
+//    return (::GetKeyState(VK_CONTROL) & 0x100) != 0;
+    // Returns different negative values on WinME and WinNT,
+    // so simply test for negative value.
+    return ::GetKeyState(VK_CONTROL) < 0;
 }
 
 // wrapper around GetWindowRect() and GetClientRect() APIs doing error checking
diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 5759320519..ea5cdb4f7f 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -4151,7 +4151,10 @@ void wxWindowMSW::InitMouseEvent(wxMouseEvent& event,
     event.m_leftDown = (flags & MK_LBUTTON) != 0;
     event.m_middleDown = (flags & MK_MBUTTON) != 0;
     event.m_rightDown = (flags & MK_RBUTTON) != 0;
-    event.m_altDown = (::GetKeyState(VK_MENU) & 0x80000000) != 0;
+//    event.m_altDown = (::GetKeyState(VK_MENU) & 0x80000000) != 0;
+    // Returns different negative values on WinME and WinNT,
+    // so simply test for negative value.
+    event.m_altDown = ::GetKeyState(VK_MENU) < 0;
 
     event.SetTimestamp(s_currentMsg.time);
     event.m_eventObject = this;