So let me get this straight.
You had a ThinkPad T61. You needed to encrypt your entire hard drive in order to comply to some FIPS standard. (Which standard exactly? FIPS 140-2 Level 2 or something else? Or do you just need some encryption, and do not have to meet any specific standard?)
You installed a hard drive that supposedly supports encryption in your old T61. The hard drive has model number HTS722016K9SA00.
Now your old T61 is dead, and you purchased another T61. When you put the old hard drive into your new T61, the computer boots normally.
Is all the above correct?
If so, the yes, you have been using your old T61 without proper protection.
First of all, not all Hitachi 7k200 hard drives support "bulk data encryption" (BDE). Here's an
incomplete list of the part numbers that do have BDE:
0A53066 – 80GB
0A53067 -100GB
0A53068 – 120GB
0A53069 – 160GB
0A53070 – 200GB
Again, this list is incomplete. If your hard drive is not among these part numbers, ask Hitachi / HGST.
Second, if your hard drive does support BDE, then you will have to
enable hard disk password in BIOS to protect your data. If you do not enable HDD password, then everyone can simply connect the hard drive to their computer and read everything. If you do enable HDD password, then the hard drive can only be read if you enter the correct password at startup.
Read HGST's guide to BDE here:
http://www.hgst.com/tech/techlib.nsf/te ... _final.pdf
Also read this thread:
http://forum.thinkpads.com/viewtopic.php?p=319400
Please be responsible and understand what you're doing, if you're working with an important project that warrants encryption!