I have installed InDesign CC from my Creative Cloud app and all went well. I tried the do the same with Photoshop and while my CC app indicates Photoshop is up to date and installed, it is not listed on my programs list like all my other apps. I am using Windows 7 Professional.
This happens when Ps app is deleted not uninstalled it. So when you try to download, it shows you that Ps CC is already installed.
Run the Cleaner tool to remove Ps CC :http://www.adobe.com/support/contact/cscleanertool.html . Restart your system and then try installing Ps again.