Check if you were using SNS login like Facebook, Twitter or Google.
If you’re stuck on splash screen refer to following topic:
If you cannot enter your password please check one of following cases:
check if ndagent process is running
check if nd3svc process is running
check if your connection to localhost (127.0.0.1) is blocked
check if any computer virus infected your computer. It was found that some computer virus like 'BrowserModifier: Win32 / Soctusser" interfere and blocks network connection