Why did my licenses stop working afer I renamed my computer?
Houdini licenses are tied to the machine name and hardware. Rename your computer back to the original name associated with your Houdini licenses.
If you would like to rename your computer, return the all the licenses back to your account at SideFX using the License Administrator.
This will release the licenses from the current machine. They will be placed back into your SideFX licensing account as uninstalled entitlements which can then be installed onto a different computer or different machine name.
Please see How do I return my licenses?