diff --git a/browser/components/shell/src/nsWindowsShellService.cpp b/browser/components/shell/src/nsWindowsShellService.cpp
index d7065446b4f..acec63fb9be 100644
--- a/browser/components/shell/src/nsWindowsShellService.cpp
+++ b/browser/components/shell/src/nsWindowsShellService.cpp
@@ -189,7 +189,6 @@ typedef struct {
 #define APP_REG_NAME L"Firefox"
 #define CLS_HTML "FirefoxHTML"
 #define CLS_URL "FirefoxURL"
-#define CPL_DESKTOP L"Control Panel\\Desktop"
 #define VAL_OPEN "\"%APPPATH%\" -requestPending -osint -url \"%1\""
 #define VAL_FILE_ICON "%APPPATH%,1"
 #define DI "\\DefaultIcon"
@@ -617,44 +616,41 @@ nsWindowsShellService::SetDesktopBackground(nsIDOMElement* aElement,
 
   // if the file was written successfully, set it as the system wallpaper
   if (NS_SUCCEEDED(rv)) {
-     bool result = false;
-     DWORD  dwDisp = 0;
-     HKEY   key;
-     // Try to create/open a subkey under HKCU.
-     DWORD res = ::RegCreateKeyExW(HKEY_CURRENT_USER, CPL_DESKTOP,
-                                   0, NULL, REG_OPTION_NON_VOLATILE,
-                                   KEY_WRITE, NULL, &key, &dwDisp);
-    if (REG_SUCCEEDED(res)) {
-      PRUnichar tile[2], style[2];
-      switch (aPosition) {
-        case BACKGROUND_TILE:
-          tile[0] = '1';
-          style[0] = '1';
-          break;
-        case BACKGROUND_CENTER:
-          tile[0] = '0';
-          style[0] = '0';
-          break;
-        case BACKGROUND_STRETCH:
-          tile[0] = '0';
-          style[0] = '2';
-          break;
-      }
-      tile[1] = '\0';
-      style[1] = '\0';
+    nsCOMPtr<nsIWindowsRegKey> regKey =
+      do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
 
-      // The size is always 3 unicode characters.
-      PRInt32 size = 3 * sizeof(PRUnichar);
-      ::RegSetValueExW(key, L"TileWallpaper",
-                       0, REG_SZ, (const BYTE *)tile, size);
-      ::RegSetValueExW(key, L"WallpaperStyle",
-                       0, REG_SZ, (const BYTE *)style, size);
-      ::SystemParametersInfoW(SPI_SETDESKWALLPAPER, 0, (PVOID)path.get(),
-                              SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
+    rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+                        NS_LITERAL_STRING("Control Panel\\Desktop"),
+                        nsIWindowsRegKey::ACCESS_SET_VALUE);
+    NS_ENSURE_SUCCESS(rv, rv);
 
-      // Close the key we opened.
-      ::RegCloseKey(key);
+    nsAutoString tile;
+    nsAutoString style;
+    switch (aPosition) {
+      case BACKGROUND_TILE:
+        style.AssignLiteral("0");
+        tile.AssignLiteral("1");
+        break;
+      case BACKGROUND_CENTER:
+        style.AssignLiteral("0");
+        tile.AssignLiteral("0");
+        break;
+      case BACKGROUND_STRETCH:
+        style.AssignLiteral("2");
+        tile.AssignLiteral("0");
+        break;
     }
+
+    rv = regKey->WriteStringValue(NS_LITERAL_STRING("TileWallpaper"), tile);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = regKey->WriteStringValue(NS_LITERAL_STRING("WallpaperStyle"), style);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = regKey->Close();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    ::SystemParametersInfoW(SPI_SETDESKWALLPAPER, 0, (PVOID)path.get(),
+                            SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
   }
   return rv;
 }
@@ -779,28 +775,24 @@ nsWindowsShellService::SetDesktopBackgroundColor(PRUint32 aColor)
 
   ::SetSysColors(sizeof(aParameters) / sizeof(int), aParameters, colors);
 
-  bool result = false;
-  DWORD  dwDisp = 0;
-  HKEY   key;
-  // Try to create/open a subkey under HKCU.
-  DWORD rv = ::RegCreateKeyExW(HKEY_CURRENT_USER,
-                               L"Control Panel\\Colors", 0, NULL,
-                               REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL,
-                               &key, &dwDisp);
+  nsresult rv;
+  nsCOMPtr<nsIWindowsRegKey> regKey =
+    do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
 
-  if (REG_SUCCEEDED(rv)) {
-    char rgb[12];
-    sprintf((char*)rgb, "%u %u %u\0", r, g, b);
-    NS_ConvertUTF8toUTF16 backColor(rgb);
+  rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+                      NS_LITERAL_STRING("Control Panel\\Colors"),
+                      nsIWindowsRegKey::ACCESS_SET_VALUE);
+  NS_ENSURE_SUCCESS(rv, rv);
 
-    ::RegSetValueExW(key, L"Background",
-                     0, REG_SZ, (const BYTE *)backColor.get(),
-                     (backColor.Length() + 1) * sizeof(PRUnichar));
-  }
-  
-  // Close the key we opened.
-  ::RegCloseKey(key);
-  return NS_OK;
+  PRUnichar rgb[12];
+  _snwprintf(rgb, 12, L"%u %u %u", r, g, b);
+
+  rv = regKey->WriteStringValue(NS_LITERAL_STRING("Background"),
+                                nsDependentString(rgb));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return regKey->Close();
 }
 
 NS_IMETHODIMP