Computer failed........

The FAQ says to back up the registry info on the old computer - That computer has failed, so I can’t. But the hard drive hasn’t failed and I can read it.
I have downloaded the latest version of the WD software and installed it. I then copied the files from the old hard drive into the directory where WD is installed. But when I run it, I get the trial version…
How can I tell it that I am a paid up member - the wdconfig file has my serial number in it !!!