Some Hilti tools have a TPS "theft protection system" built into the electronics.
"Hilti TPS consists of Company Card, Activation Key, and electronic module inside tool. Company-specific theft protection code is set in each tool using Company Card. Authorized users receive Activation Key, which is needed to electrically unlock tools. User connects tool to power supply, holds Activation Key to tool, and begins work. If tool is stolen, it will lock after 20 min and cannot be restarted without Activation Key."
If you don't have the activation key, you would need to return the tool to Hilti, and explain why you have it if you're not the person who purchased the tool.
I believe Hilti only includes this in expensive tools like their more powerful rotary hammers and breakers that can cost over a grand.
Hilti has a patent on this that would seem to cover any similar tools, and would need to be licensed unless a run around was found.
http://www.freepatentsonline.com/y2012/0111589.html