cdy1, the first thing you need to do is to find the reason why updates are failing so head to Control Panel -> Windows Updates -> View Update History (top-left). Look in the "Status" column for any that show "Failed", and if you find one, double-click on the entry to view the details in a new window. Let me know what the failure code is. Do the same for another two recent failed updates.
If you can't find anything useful there then I can tell you how to use Event Viewer which may pinpoint the exact cause of the failures.