You might want to call them.
Digital locker is built into some (perhaps all, not sure) versions of Vista - basically it will take your key ans store it online. Once you get a new version of Vista running, see if you can get that key back from the online source - do it soon, Digital Locker closes in Aug 09.
Also, I cannot help you with this any further as *I* have no way of knowing whether you're really talking about your own hardware or not - and I am certainly not going to help decrypt a HD that might end up belonging to someone else, nor am I going to *attempt* to do so for free. Mind you I am not calling you a liar - I am just saying that I don't even know you, much less have no way of verifying it.
There are plenty of data recovery solutions online, you'll have to find them and contact them yourself.