Using Puck as a single button keyboard

Unless you type save(), all the code that was running on Puck.js will be lost - so I think that was your problem initially when you removed the battery. It's worth reading http://www.espruino.com/Quick+Start#star­t-writing-code- for an intro, and how to write code that runs at startup.

What drivers did you reinstall? Puck.js should need no drivers, so all I can assume is that it is the drivers for your Bluetooth LE dongle that Windows is complaining about?

However the 3 LEDs lighting up points to some problem in Puck.js's software. It's most likely related to bonding.

When you do manage to connect, please could you run the following code on Puck.js:

var f = require("Flash");
for (var i=119;i>=115;i--) {
  print(i);
  f.erasePage(i*4096);
}

That should clear out any saved code, along with the bonding information - which will hopefully return it to normal and fix the 3 LED lighting issue. I'm hoping to try and fix that properly in a later release, but am having trouble reproducing it here, and it seems to be an internal issue in Nordic's software libraries :(