Unlocking password from different computer

WD External Drives WD Portable Drives
1

I received a 100% recovered hdd volume (C:) back from “Ontrack” with password protection, instructed to connect it to the original computer and proceed from there. But I’ve no idea in how far that process is under my control and don’t want anything to happen when a different computer is involved in unlocking. My main problem is that the two recovery partitions behind “C” on the fixed drive seem lost and are inaccessible. So according to information from the MS uefi boot partition(s), (still intact) at boot time, my computer neither is operational as, nor is the attached drive accessible. My questions are: 1. Is unlocking as per the subject title possible? 2. once that is done, will the OS be enacted automatically from the WD drive? 3. if not, apart from getting new recovery media from Toshiba, is there another way to boot into my system and access the WD drive for recovering my fixed drive? and 4. Would the WD drive normally contain a boot sector? I’ve mentioned the latter to Ontrack in emails twice, without getting it answered.
Thanks