Index: /trunk/src/VBox/Installer/win/VirtualBox.wxs
===================================================================
--- /trunk/src/VBox/Installer/win/VirtualBox.wxs	(revision 55101)
+++ /trunk/src/VBox/Installer/win/VirtualBox.wxs	(revision 55102)
@@ -108,4 +108,5 @@
     </Condition>
 
+    
     <!-- *************************** Upgrade packages only ******************************* -->
     <!-- Minimum and Maximum specify the range of versions we are supposed to update with this upgrade.
@@ -164,4 +165,24 @@
                   DllEntry="UninstallTAPInstances" Execute="deferred" Return="check" Impersonate="no"/>
 
+    <Property Id="VBOXDEPENDENCY" Secure="yes">
+        <DirectorySearch Id="VBoxInstallDir" Path="[EXISTINGINSTALLDIR]">
+            <FileSearch Name="dependency.dep"/>
+        </DirectorySearch>
+    </Property>
+    
+    <!--
+                            install upgrade uninstall
+    VBOXDEPENDENCY             0      1/0      1/0
+    UPGRADINGPRODUCTCODE       0       1        0
+    final                      0       1        0
+    not final                  1       0        1
+    -->
+
+    <Condition Message="It was detected an application which has been using currently installed VirtualBox version. 
+    You must remove this application before continuing installation. 
+    See the file dependency.dep in the VirtualBox installation directory for details. ">
+        NOT (VBOXDEPENDENCY AND UPGRADINGPRODUCTCODE)
+    </Condition>
+    
     <!-- Detect old Sun installation -->
     <!-- Force a manual uninstall of an already installed Sun VirtualBox version first -->