1) No, as only encrypted files are actually stored on the hard disk. Encrypted files are only accessible while your computer and Boxcryptor is running.
2) Same answer.
If your notebook gets stolen, your encrypted data is only at risk if the thief can access your running operating system and Boxcryptor. However, this is pretty easy to prevent using operating system features (e.g. automatically lock your computer, encrypt your hard disk, etc.) and/or using the app protection feature of Boxcryptor - and even in such a case, you could remotely disconnect your notebook so that it will reset Boxcryptor to factory defaults automatically whenever the notebook is online again.