CC doesn't start after download

Hi!

I bought today DC, I downloaded it on my Windows PC, but after downloading the app does not open. The window remains completely white, from the top right wheel I can only access the help or exit. I followed step-by-step support information, doing every operation, and then rebooting the PC every time. Despite having shut down all programs and closing of all possible and impossible accounts, I can not throw two files from the OOBE folder, fylesync, and obm. The PC tells me they are open in CCloud! What can I do? Do I have to uninstall CC again?

Thank you!

Antonia