Macbook Air does not want to update to Yosemite 10.10.3

Question

My Macbook Air is running on Yosemite 10.10.2 and I want to update it to the current version of 10.10.3.  However, I cannot do that as it is not letting me update anything.  When I click on the update tab in the app store, in the left hand corner, it keeps "Checking for updates" and will not allow me to update anything.  I can click on the tab to update but nothing will happen.  I also need to update my iTunes and it is not allowing me to do so.  This is HIGHLY annoying and I have high speed internet so I know it isn't that.  Is anyone else having this problem?  Please help!

Answer 1

Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad and start typing the name.
The title of the Console window should be All Messages. If it isn't, select
          SYSTEM LOG QUERIES ▹ All Messages
from the log list on the left. If you don't see that list, select
          View ▹ Show Log List
from the menu bar at the top of the screen.
Click the Clear Display icon in the toolbar. Then take the action that isn't working the way you expect. Select any lines that appear in the Console window. Copy them to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.
The log contains a vast amount of information, almost all of which is irrelevant to solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.
Please don't indiscriminately dump thousands of lines from the log into this discussion.
Please don't post screenshots of log messages—post the text.
Some private information, such as your name or email address, may appear in the log. Anonymize before posting.
When you post the log extract, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the forum software. Please post the text on Pastebin, then post a link here to the page you created.