diff --git a/toolkit/mozapps/downloads/content/downloads.js b/toolkit/mozapps/downloads/content/downloads.js
index 89a7728e3fdd..3c6080d01379 100644
--- a/toolkit/mozapps/downloads/content/downloads.js
+++ b/toolkit/mozapps/downloads/content/downloads.js
@@ -42,6 +42,7 @@
 const kObserverServiceProgID = "@mozilla.org/observer-service;1";
 const NC_NS = "http://home.netscape.com/NC-rdf#";
 const PREF_BDM_CLOSEWHENDONE = "browser.download.manager.closeWhenDone";
+const PREF_BDM_ALERTONEXEOPEN = "browser.download.manager.alertOnEXEOpen";
 
 var gDownloadManager  = null;
 var gDownloadListener = null;
@@ -313,6 +314,33 @@ function onDownloadOpen(aEvent)
 
       if (f.exists()) {
         // XXXben security check!  
+        if (f.isExecutable()) {
+          var dontAsk = false;
+          var pref = Components.classes["@mozilla.org/preferences-service;1"]
+                              .getService(Components.interfaces.nsIPrefBranch);
+          try {
+            dontAsk = !pref.getBoolPref(PREF_BDM_ALERTONEXEOPEN);
+          }
+          catch (e) { }
+          
+          if (!dontAsk) {
+            var strings = document.getElementById("downloadStrings");
+            var name = aEvent.target.getAttribute("target");
+            var message = strings.getFormattedString("fileExecutableSecurityWarning", [name, name]);
+
+            var title = strings.getString("fileExecutableSecurityWarningTitle");
+            var dontAsk = strings.getString("fileExecutableSecurityWarningDontAsk");
+
+            var promptSvc = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(Components.interfaces.nsIPromptService);
+            var checkbox = { value: false };
+            var open = promptSvc.confirmCheck(window, title, message, dontAsk, checkbox);
+            
+            if (!open) 
+              return;
+            else
+              pref.setBoolPref(PREF_BDM_ALERTONEXEOPEN, !checkbox.value);              
+          }        
+        }
         f.launch();
       }
       else {
diff --git a/toolkit/mozapps/downloads/locale/downloads.properties b/toolkit/mozapps/downloads/locale/downloads.properties
index 89aaa42d5044..a970a5ad375c 100644
--- a/toolkit/mozapps/downloads/locale/downloads.properties
+++ b/toolkit/mozapps/downloads/locale/downloads.properties
@@ -36,4 +36,9 @@ fileDoesNotExistShowErrorUnix=%S does not exist. (Perhaps you moved it from the
 
 chooseAppFilePickerTitle=Open With...
 downloadsTitle=%S%% of 1 file - Downloads
-downloadsTitleMultiple=%S%% of %S files - Downloads
\ No newline at end of file
+downloadsTitleMultiple=%S%% of %S files - Downloads
+
+fileExecutableSecurityWarning="%S" is an executable file. Executable files may contain viruses or other malicious code that could harm your computer. Use caution when opening this file. Are you sure you want to launch "%S"?
+fileExecutableSecurityWarningTitle=Open Executable File?
+fileExecutableSecurityWarningDontAsk=Don't ask me this again
+
diff --git a/toolkit/mozapps/installer/windows/wizard/setup/dialogs.c b/toolkit/mozapps/installer/windows/wizard/setup/dialogs.c
index 32b5901fe8e6..af4fe09a228d 100644
--- a/toolkit/mozapps/installer/windows/wizard/setup/dialogs.c
+++ b/toolkit/mozapps/installer/windows/wizard/setup/dialogs.c
@@ -41,6 +41,9 @@
 // commdlg.h is needed to build with WIN32_LEAN_AND_MEAN
 #include <commdlg.h>
 
+// Turn off default to safe upgrade for 0.8... until we can guarantee that we won't be deleting other files. 
+#define DEFAULT_SAFE_UPGRADE FALSE
+
 static WNDPROC OldListBoxWndProc;
 static DWORD   gdwACFlag;
 static BOOL    gDidShowUpgradePanel;
@@ -118,7 +121,7 @@ void InitSequence(HINSTANCE hInstance)
     // If we're not showing the Upgrade dialog, we need to set some state to
     // tell the installer to default to a Safe Install. 
 
-    sgProduct.doCleanupOnUpgrade = TRUE;
+    sgProduct.doCleanupOnUpgrade = DEFAULT_SAFE_UPGRADE;
   }
 
   if (diSelectComponents.bShowDialog) {
@@ -337,6 +340,7 @@ LRESULT CALLBACK DlgProcLicense(HWND hDlg, UINT msg, WPARAM wParam, LONG lParam)
     // Check the "Decline" Radio button by default. 
     CheckDlgButton(hDlg, IDC_RADIO_DECLINE, BST_CHECKED);
     SendMessage(GetDlgItem(hDlg, IDC_RADIO_DECLINE), BM_SETCHECK, BST_CHECKED, 0);
+    PropSheet_SetWizButtons(GetParent(hDlg), PSWIZB_BACK);
 
     // License Text
     lstrcpy(szBuf, szSetupDir);
@@ -592,7 +596,7 @@ void CheckForUpgrade(HWND aPanel, int aNextPanel)
       if(sgProduct.mode == NORMAL)
         nextPanel = DLG_UPGRADE;
       else {
-        sgProduct.doCleanupOnUpgrade = TRUE;
+        sgProduct.doCleanupOnUpgrade = DEFAULT_SAFE_UPGRADE;
         nextPanel = aNextPanel;
       }
     }