BitLocker Encrypted drive not showing anymore

I have 2TB hard drive with partitions, one have windows installed on and the other is BitLocker encrypted for data storage. I dont know what happend to my pc while I was at work but my pc was restarted when I got home and now my computer only shows one diskdrive (C, where windows is installed). BitLocked encrypted drive D does not show. It does show when I open disk management but it has no drive letter. See screenshot. What are my options? Please dont tell me that my 1765GB of encrypted data is lost :S

My first bet would be to make a Ubuntu Live cd (Or even better a forensics Helix boot cd but thats probably over the top!), boot into that and see if you are able to mount the partition.. If you can then I would backup the data somewhere if possible... I think im right in saying that you can still decrypt the encrypted data if you copy it elsewhere but I haven't had much experience of bitlocker, only truecrypt.

My personal opinion is not to do anything within Windows as if it doesn't see the data or partition it may start harming your data.... Good to know my 4 years of Forensic Computing isnt going to waste... I think the above is a good start.

Hopefully others out there will have some more / easier suggestions