Q: iCloud photos is not enabled

Hey Horstfromab,

Thanks for the question. You can enable photo stream on your PC by following these steps:

PC: Open the iCloud Control Panel for Windows and select the checkbox for Photos (Photo Stream in iCloud Control Panel 2.x). You can click the Options button to verify that My Photo Stream is enabled and adjust the settings. Be sure to click Apply when done.

 

via iCloud: My Photo Stream FAQ

http://support.apple.com/kb/HT4486

Thanks,

Matt M.