With the latest release of Windows 10 (build 9926) I decided to do a clean install and save none of my previous files. One downside to doing this is that the pen button doesn’t automatically open OneNote anymore. There is a very simple solution for this: Press the Windows key and type Devices. Select “Devices and Printers” when Cortana suggests it. From the Devices and Printers Control Panel select “Add a device” from the menu. At this point you’ll want to press the purple button on the pen and hold it until the little green light comes on. On the list of devices found should be “Surface Pen”. Select that and after a little while it will be connected. Test it out by pressing the button and the new OneNote app should appear. If this doesn’t work, either leave a message here or Tweet me @spatacoli and I’ll see if I can help you out.