Well, it's Skype making trouble again. If Skype starts before IIS then it'll hog port 80 and not give it back.
So, how do you fix this. Well, a simple Google search should give you everything you need. But I'm writing this down it case I forget (and hopefully by the process of writing I'll remember more).
To force Skype not to use port 80 follow these steps:
Open Skype, Select Tools -> Options. You should get this if you're running version 3.6.0.

Now select Advanced and then Connection.
Make sure Use port 80 and 443 as alternatives for incoming connections is unchecked.
Also make sure that the number in the Use port text box is not port 80.
That's it. Once you restart Skype port 80 should now be free.
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