Index: xbmc.vcproj
===================================================================
--- xbmc.vcproj	(revision 32865)
+++ xbmc.vcproj	(working copy)
@@ -1218,6 +1218,12 @@
 				Name="Database"
 				Filter="">
 				<File
+					RelativePath=".\xbmc\AddonDatabase.cpp">
+				</File>
+				<File
+					RelativePath=".\xbmc\AddonDatabase.h">
+				</File>
+				<File
 					RelativePath=".\xbmc\music\Album.cpp">
 				</File>
 				<File
Index: xbmc/AddonDatabase.cpp
===================================================================
--- xbmc/AddonDatabase.cpp	(revision 0)
+++ xbmc/AddonDatabase.cpp	(revision 0)
@@ -0,0 +1,31 @@
+#include "AddonDatabase.h"
+#include "settings/Settings.h"
+#include "FileSystem/Directory.h"
+
+using namespace XFILE;
+
+/*
+ * Returns true if the specified addon is installed on the system.
+ */
+bool CAddonDatabase::HasAddon(const CStdString& addonID) {
+  // Check if exists as full path.
+  // e.g. "special://home/scripts/XBMC Subtitles"
+  if (CDirectory::Exists(addonID)) {
+    return true;
+  }
+
+  // Check if "script.NAME" exists.
+  // Allows for "script.xbmc.subtitles" -> "special://home/scripts/xbmc subtitles"
+  if (addonID.Left(7).Equals("script.")) {
+	CStdString scriptName    = addonID.Mid(7);
+	scriptName.Replace(".", " ");
+    CStdString scriptsFolder = g_settings.GetScriptsFolder() + "/" + scriptName;
+
+    if (CDirectory::Exists(scriptsFolder.c_str())) {
+      return true;
+    }
+  }
+
+  // Default
+  return false;
+}
\ No newline at end of file
Index: xbmc/AddonDatabase.h
===================================================================
--- xbmc/AddonDatabase.h	(revision 0)
+++ xbmc/AddonDatabase.h	(revision 0)
@@ -0,0 +1,8 @@
+#include "utils/StdString.h"
+
+class CAddonDatabase
+{
+public:
+  /* Returns true if the specified addon is installed on the system. */
+  static bool HasAddon(const CStdString& addonID);
+};
\ No newline at end of file
Index: xbmc/GUIInfoManager.cpp
===================================================================
--- xbmc/GUIInfoManager.cpp	(revision 32865)
+++ xbmc/GUIInfoManager.cpp	(working copy)
@@ -85,6 +85,7 @@
 #include "utils/log.h"
 
 #include "interfaces/info/InfoBool.h"
+#include "AddonDatabase.h"
 
 using namespace std;
 using namespace XFILE;
@@ -449,6 +450,10 @@
       return AddMultiInfo(GUIInfo(bNegate ? -SYSTEM_GET_BOOL : SYSTEM_GET_BOOL, ConditionalStringParameter(strTest.Mid(15,strTest.size()-16)), 0));
     else if (strTest.Left(15).Equals("system.setting(")) 
       return AddMultiInfo(GUIInfo(bNegate ? -SYSTEM_SETTING : SYSTEM_SETTING, ConditionalStringParameter(strTest.Mid(15,strTest.size()-16)), 0));
+    else if (strTest.Left(16).Equals("system.hasaddon(")) {
+      int addon = ConditionalStringParameter(strTest.Mid(16, strTest.GetLength() - 17));
+      return AddMultiInfo(GUIInfo(bNegate ? -SYSTEM_HAS_ADDON: SYSTEM_HAS_ADDON, addon));
+    }
   }
   // library test conditions
   else if (strTest.Left(7).Equals("library"))
@@ -2360,6 +2365,12 @@
             bReturn = false;
         }
         break;
+      case SYSTEM_HAS_ADDON:
+        {
+          CStdString addon = m_stringParameters[info.GetData1()];
+          bReturn = CAddonDatabase::HasAddon(addon);
+        }
+	    break;
       case CONTROL_GROUP_HAS_FOCUS:
         {
           CGUIWindow *window = GetWindowWithCondition(contextWindow, 0);
Index: xbmc/GUIInfoManager.h
===================================================================
--- xbmc/GUIInfoManager.h	(revision 32865)
+++ xbmc/GUIInfoManager.h	(working copy)
@@ -408,6 +408,7 @@
 #define SYSTEM_OPENGL_RENDERER      708
 #define SYSTEM_OPENGL_VERSION       709
 #define SYSTEM_SETTING              710
+#define SYSTEM_HAS_ADDON            711
 
 #define LIBRARY_HAS_MUSIC           720
 #define LIBRARY_HAS_VIDEO           721