Faisal,
You need to explain what “I can’t unlock it using older key” means… when you launch the new install, go to MyEclipse > Update Subscription Information… have you entered your subscription information here? Does it say anything?
Also Nipun is correct that the “global” location for your subscription information is at that location, if MyEclipse cannot write to that location, it will ask you for your subscription information each time you start.