Purchased access to Creative Cloud today - chose the apps that I needed to upgrade, started with Photoshop.
It's been hours (9:15AM MST 'til now 4pm) & the message remains "Photoshop is downloading now" . . .
I'm running Win7, i7 processor, 6GB RAM, 37GB available on C drive . . .
Need to work on projects for clients . .
Link for Download & Install & Setup & Activation problems may help
And, some things to try
Please read, and reply back here with information https://forums.adobe.com/thread/1499014