Check if Windows registry value exists before trying to delete

plexpy/windows.py

@@ -150,8 +150,16 @@ def set_startup():
             return False
 
     else:
+        # Check if registry value exists
         try:
             registry_key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, startup_reg_path, 0, winreg.KEY_ALL_ACCESS)
+            winreg.QueryValueEx(registry_key, common.PRODUCT)
+            reg_value_exists = True
+        except WindowsError:
+            reg_value_exists = False
+
+        if reg_value_exists:
+            try:
                 winreg.DeleteValue(registry_key, common.PRODUCT)
                 winreg.CloseKey(registry_key)
                 logger.info("Removed Tautulli from Windows system startup registry key.")