Suddenly Google Play stopped working and now it is always asking me to provide an existing account or that i create a new one. When i try to use my existing one, it tells me that that account is already installed on Android and it returns back to the "Provide existing or new account" screen. When i remove that account from my device, it allows me to provide my existing account, we walk through the screens, i skip the credit card screen, and afterwards Play does not start. When i start Play again, it again asks me for an account...
Using the same account within the email app works without problems, syncing contacs, calendar etc. works as well without any issue.
How can i find out whats going wrong with Play now after it worked nicely since i have purchased the device?
This worked for me.
go to settings -> apps -> Google play.
Disable the app, uninstall the updates and re-enable it.
Try the above methods... If they don't work I would recommend you to flash gapps for your device with proper android version and architecture... This worked out for me. I'm running stock rom and faced the same issues. Also don't forget to wipe cache from recovery