Some time ago I damaged - by accident of course - my laptop with Windows 7 and BitLocker encryption enabled. After I have moved to new laptop I wanted to copy data. So I put old disk to USB hard disk case, connected to my machine and nothing happend, Windows 7 couldn't detect it. I started searching for possible solutions, but without luck (only some hardcore posts with thousands of strange steps). Finally I found what was wrong. Windows 7 was able to see it, but haven't assigned drive letter to this disk.
So I just opened "Disk Management", found proper disk and assigned letter.
Then window with recovery key appeard.
I have entered it and I was able to copy my data :)