When the laptop was set up it was simply switched on as it came from the manufacturer, and set up with Microsoft Office and your data transferred to it. We did not add any additional software that would encrypt the hard drive. As previously discussed all windows operating systems come with encryption capabilities built in called Bitlocker, this feature usually needs to be enabled. This can sometimes be turned on automatically by the Windows OS depending on how you sign in to the Laptop or by other manufacturer software that they install to Windows before it is shipped out from the manufacturer.
Bring old laptop back to life and back up files
Can you stick your drive in another, as similar as possible, laptop and boot as normal. I very much doubt the drive was locked to any specific hardware.If you can find out what encryption software was used in the first place you stand a better chance of decrypting it, there is usually a tool available for these things.
HP machines have pre-installed security tools, I think contacting HP support might be your best bet, I've read threads on the internet where people have done that, send off their drives, the passwords and a drive to copy the data too and it worked
After making these suggestions to the support company one of the other engineers remembered he had some old de-encryption software at home and it worked - desktop items recovered n'all \o/
I don't understand why putting the drive in a similar machine wouldn't work unless the encryption is pre-boot or from the bios etc.