Okay, so get this: I've tried everything known to man in order to fix this same problem everyone has been having, and only one thing worked for me. After un-checking compatibility mode for all users, deleting the registry key, AND re-installing steam multiple times, I tried one last thing...go into steam settings, and under the Downloads+Clouds tab, change your region to better match where you are. I have NO idea why, but this fixed my problem. Don't ask! :-)