My 2015 licence is letting me input, so it is valid, however I cannot edit PDF's. I have already entered it in to the key screen, so it won't let me attached to this account as it is already in use.

Hi danielb94,

As per the issue description mentioned above, you are unable to edit pdf, is that correct?

As we have checked the account details using the email address you are logged into the forums, you have subscription for creative cloud all apps. Could you check if you are using Acrobat to edit pdf files? You can check the same using this link: Identify the product and its version for Acrobat and Reader DC

If using Reader, you can also download Acrobat using the steps given here: Learn how to download your Adobe Creative Cloud apps and check.

Thanks,

Shivam