diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index f61e40ef77..17420d271d 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -362,7 +362,7 @@ QString QWindowsContext::registerWindowClass(const QWindow *w, bool isGL)
         style = CS_DBLCLKS;
         if (w->inherits("QTipLabel") || w->inherits("QAlphaWidget")) {
             if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
-                && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)) {
+                && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))) {
                 style |= CS_DROPSHADOW;
             }
             cname += QStringLiteral("QToolTip");
@@ -375,7 +375,7 @@ QString QWindowsContext::registerWindowClass(const QWindow *w, bool isGL)
         cname += QStringLiteral("QPopup");
         style = CS_DBLCLKS|CS_SAVEBITS;
         if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
-            && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+            && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)))
             style |= CS_DROPSHADOW;
         icon = false;
     } else {
diff --git a/src/widgets/dialogs/qwizard.cpp b/src/widgets/dialogs/qwizard.cpp
index 8a75353c86..ac19ec8d22 100644
--- a/src/widgets/dialogs/qwizard.cpp
+++ b/src/widgets/dialogs/qwizard.cpp
@@ -573,7 +573,7 @@ public:
         }
 #if !defined(QT_NO_STYLE_WINDOWSVISTA)
         if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA
-            && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)
+            && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))
             vistaInitPending = true;
 #endif
     }
diff --git a/src/widgets/kernel/qwhatsthis.cpp b/src/widgets/kernel/qwhatsthis.cpp
index 88c41a5fba..9d3493dc8a 100644
--- a/src/widgets/kernel/qwhatsthis.cpp
+++ b/src/widgets/kernel/qwhatsthis.cpp
@@ -291,7 +291,7 @@ void QWhatsThat::paintEvent(QPaintEvent*)
     bool drawShadow = true;
 #if defined(Q_WS_WIN)
     if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
-        && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+        && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)))
     {
         BOOL shadow;
         SystemParametersInfo(SPI_GETDROPSHADOW, 0, &shadow, 0);
diff --git a/src/widgets/styles/qstylefactory.cpp b/src/widgets/styles/qstylefactory.cpp
index ef555fbdb1..9ed452b516 100644
--- a/src/widgets/styles/qstylefactory.cpp
+++ b/src/widgets/styles/qstylefactory.cpp
@@ -218,12 +218,12 @@ QStringList QStyleFactory::keys()
 #endif
 #ifndef QT_NO_STYLE_WINDOWSXP
     if (!list.contains(QLatin1String("WindowsXP")) &&
-        (QSysInfo::WindowsVersion >= QSysInfo::WV_XP && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+        (QSysInfo::WindowsVersion >= QSysInfo::WV_XP && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)))
         list << QLatin1String("WindowsXP");
 #endif
 #ifndef QT_NO_STYLE_WINDOWSVISTA
     if (!list.contains(QLatin1String("WindowsVista")) &&
-        (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+        (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)))
         list << QLatin1String("WindowsVista");
 #endif
 #ifndef QT_NO_STYLE_MOTIF
diff --git a/src/widgets/styles/qwindowsstyle.cpp b/src/widgets/styles/qwindowsstyle.cpp
index 99a78520d5..1cd53c8073 100644
--- a/src/widgets/styles/qwindowsstyle.cpp
+++ b/src/widgets/styles/qwindowsstyle.cpp
@@ -121,7 +121,7 @@ QWindowsStylePrivate::QWindowsStylePrivate()
 {
 #if defined(Q_OS_WIN) && !defined(Q_OS_WINCE)
     if ((QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA
-        && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)) {
+        && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))) {
         QSystemLibrary shellLib(QLatin1String("shell32"));
         pSHGetStockIconInfo = (PtrSHGetStockIconInfo)shellLib.resolve("SHGetStockIconInfo");
     }
@@ -1045,7 +1045,7 @@ QPixmap QWindowsStyle::standardPixmap(StandardPixmap standardPixmap, const QStyl
     case SP_VistaShield:
         {
             if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA
-                && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based
+                && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)
                 && pSHGetStockIconInfo)
             {
                 QPixmap pixmap;
@@ -1187,7 +1187,7 @@ int QWindowsStyle::styleHint(StyleHint hint, const QStyleOption *opt, const QWid
     case SH_LineEdit_PasswordCharacter:
         {
 #ifdef Q_OS_WIN
-            if (widget && (QSysInfo::WindowsVersion >= QSysInfo::WV_XP && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)) {
+            if (widget && (QSysInfo::WindowsVersion >= QSysInfo::WV_XP && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))) {
                 const QFontMetrics &fm = widget->fontMetrics();
                 if (fm.inFont(QChar(0x25CF)))
                     ret = 0x25CF;
@@ -3190,7 +3190,7 @@ QIcon QWindowsStyle::standardIconImplementation(StandardPixmap standardIcon, con
     case SP_VistaShield:
         {
             if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA
-                && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based
+                && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)
                 && pSHGetStockIconInfo)
             {
                 icon.addPixmap(proxy()->standardPixmap(SP_VistaShield, option, widget)); //fetches small icon
diff --git a/src/widgets/styles/qwindowsvistastyle.cpp b/src/widgets/styles/qwindowsvistastyle.cpp
index c18b2266b8..78d4e7b9ce 100644
--- a/src/widgets/styles/qwindowsvistastyle.cpp
+++ b/src/widgets/styles/qwindowsvistastyle.cpp
@@ -138,7 +138,7 @@ bool QWindowsVistaStylePrivate::useVista()
 {
     return (QWindowsVistaStylePrivate::useXP() &&
             (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA &&
-             QSysInfo::WindowsVersion < QSysInfo::WV_NT_based));
+             (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)));
 }
 
 /*!
diff --git a/src/widgets/styles/qwindowsxpstyle.cpp b/src/widgets/styles/qwindowsxpstyle.cpp
index 8b745ba114..f40bd22fca 100644
--- a/src/widgets/styles/qwindowsxpstyle.cpp
+++ b/src/widgets/styles/qwindowsxpstyle.cpp
@@ -866,7 +866,7 @@ void QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeDa
         inspectData = (tmt_transparentcolor != 0 || tmt_borderonly || proporigin == PO_PART || proporigin == PO_STATE);
 
         // ### This is a vista-specific workaround for broken alpha in titlebar pixmaps
-        if ((QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)) {
+        if ((QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))) {
             if (themeData.partId == WP_CAPTION || themeData.partId == WP_SMALLCAPTION)
                 inspectData = false;
         }
diff --git a/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp b/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
index b96d3f7095..d9862affed 100644
--- a/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
+++ b/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
@@ -213,10 +213,10 @@ void tst_QStyle::testStyleFactory()
 #endif
 #ifdef Q_WS_WIN
     if (QSysInfo::WindowsVersion >= QSysInfo::WV_XP &&
-        QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)
+        (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))
         QVERIFY(keys.contains("WindowsXP"));
     if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA &&
-        QSysInfo::WindowsVersion < QSysInfo::WV_NT_based)
+        (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))
         QVERIFY(keys.contains("WindowsVista"));
 #endif