The license key file is not stored anywhere in the IDQ installation. It's read during the installation process (so you have to somehow transfer it to the server's local storage), and the contents of the license service are created depending on the contents of the license file. And that's it. The license file (as sent by Informatica Shipping) is NOT stored on the Informatica server (at least not by the Informatica software itself).
Normally, if you can't find the license file, then simply raise a shipping request at Informatica Shipping (or GCS = Informatica Global Customer Support, they will forward the shipping request to Informatica Shipping), then you'll get a new license key file. Which you can then use to re-install the software.
If I understand correctly, in your case the "physical" installation is still ok but the DB contents are lost AND you can't find the license file. So you should again request a new license key file. You can then create a new domain DB, recreate the license service and the application services, and then you can start working with the software again.
To all GCS folks, have I missed anything here?
Thanks for providing information Nico.Our IDQ previous license was not expired .So will shipping again license key will add to cost or no cost would be charged from Informatica.
Getting a new license key file costs you one thing: one call or one email. That's all. Informatica won't charge you anything for a new license key file.
You also have an option to raise a Shipment case with Informatica and get all the license required. For raising a case you will require a proper Project Number . So if you have so, please go ahead and do the same.