Sorry you are having trouble with the Dato Launcher. It sounds like you found a bug, but we need to collect more information about your system to understand the problem. Please open a support ticket at http://dato.com/support, and attach your Dato Launcher log file. This should be located at
C:\Users\<your user name>\AppData\Roaming\Dato Launcher\dato-launcher-install-log.txt.
To get IPython Notebook working again, please try using the "Terminal" button in the Launcher, and then type "ipython notebook" in the CMD window.
Let me know if this doesn't work!