iTunes links not working

Folks,

Am running iTunes 11.1.4.62 on Windows 7 64-bit and am having a few issues, which I suspect are related:

When I buy a season pass and emails arrive with a link to download newly posted shows that have already been purchased, the links do not open iTunes - they just take me to the page to download iTunes, which I already have installed. This is not browser-related, it happens with all browsers (Safari, Firefox, IE.)

Links on the web to go to the App Store to download an app also do the same thing - instead of loading iTunes and taking me to the App Store they just bring to the page to download iTunes.

Lastly, every time I access the App Store, I get an email saying that it has been accessed from a new machine, which is not true. (And I frequently, though not always, get messages telling me that my computer is not authorized, even though it is - and when i click on 'authorize" it tells me that it is already authorized.)

Anyway, the first issue is most important... btw I have removed iTunes and done a clean re-install several times, but this has not fixed the problem.

Thanks for any suggestions!

-- Bob