If your stylus is not recognized by your computer, the tip is either broken off or missing. You can solve this, by inserting a replacement tip into the stylus.
Some styluses come with a replacement tip. If yours did not, you require a Replacement Tip Set suitable for your stylus. If a Replacement Tip Set is not available for your stylus, you will need to replace the entire stylus.
Note: If the tip is completely broken off and you are not able to remove it, you will also need to replace the entire stylus.
How to Replace the Tip of My Stylus
For instructions on how to replace the tip of your stylus, see Instructions for Replacing an Active Stylus Tip and follow the steps.