If you need to re-activate your license key due to hardware change, try the steps in http://www.intel.com/support/motherboards/server/ss4000-e/sb/CS-022915.htm http://www.intel.com/support/motherboards/server/ss4000-e/sb/CS-022915.htm. If you need license key for new clients, well I'm sorry that won't be available since the product has been End-of-Life for more than 3 years. See http://www.intel.com/support/motherboards/server/ss4000-e/sb/CS-030443.htm http://www.intel.com/support/motherboards/server/ss4000-e/sb/CS-030443.htm.
I tried to use the link for reactivation you suggested, but after sending old licence file to the email address written in the article, the reply was that the key was used on another computer and that I have to ask for new one.
We did onle some hardware changes, so I needed reactivate old key. What should I do now?
Unfortunately no. The resources are not available to create and sell new licenses, or reactivate old licenses
If you're using Windows*, have you considered Windows* Backup? Windows* Backup provides the ability to backup to a network share. If you're using a Linux distro are there equivalent applications available?