It happened with you that when you was trying to install an update from Windows Update, you got a message saying install the update again. This is just because your update is not installed correctly the first time or the windows update settings of your computer can not detect the update. For windows 8 operating system follow the methods describe below.
Firstly you need to review the installation history. To do this you need to press the Windows + C key combination from your keyboard and then click the Search charm.
In the search box type windows update and click on Settings. After that you need to click on View update history. Now locate the novel entry for the specific update.
In the Status column if the entry states Successful that means update was installed. If states Pending in the Status column that means update was not installed.
If still you face any problem then go for windows 8 help support to resolve your problem.