Toolbar>Update>> Refresh Updates.....
Don't do the Update installed products on the drop down... choose the last line option REFRESH UPDATES... should work... at least it has for the other 100 or so people who have asked this question w/o looking for an answer already posted in here.
If an answer solves your issue, click on the "Accept as Solution" button! Makes it easier for people to find answers to similar questions that have already been posted.
