I was unclear as to what update you installed. It also might help what build of 5.1.6 you have as one had an issue with sata drives on lenovo machines. Have you tried turning SATA to Compatibility mode in the bios?
I'd just like to add, that when we rolled this out to all our company laptops, we rolled out a daily backup solution first. Given all the bad things that can happen or go wrong when you encrypt a drive, I think it's a must... this is just my 2 cents.
doing force decrypt twice was a bad move - now you've double-decrypted some sectors. A normal decrypt would understand not to decrypt the same sector twice, but a force decrypt does exactly what you tell it to.
I'd stop right now and call support, but getting the data back now will be tough.
The original problem is likely from the Rescue and Recovery application.
When you run the update to this program, it rewrites the MBR. This can sometimes be fixed by going into the Safetech cd and writing the Safeboot MBR back to the drive.
As a general rule - before I make any changes to the drive, I check if I can see any data on the drive and copy it up to the network. I have had more then one drive become nonreadable after removes / force decrypt failures.
I'm guessing this is from a bios update. I'm sorry to say I have not had much luck getting data off of Lenovos after this update, since it gives the error that safeboot is not installed with normal recovery. With the force decrypt you might have had a chance but running it twice probably broke it. I agree with Safeboot you should log a ticket with support and have them attempt to recover this data.
I also just received an IBM laptop with this error. The owner had loaded an IBM backup program which must have messed with the MBR. I booted into Wintech, authenticated to the hard drive using the Database SDB key, and then went to Disk --> Restore EEPC MBR. It worked like a charm and the system booted right up again.