I have a HP Pavilion xe4230 computer that was running XP when it
was running OK.  Something has happened and now the hard disk is
locked and I cannot access the hard drive.  I have the bios p/w and
have changed it to no p/w.  The BIOS should unlock the drive with
no p/w.  The bios says the user p/w is clear and the administrators'
p/w is clear and the hard drive lock is 'disabled'.  I have flashed
the bios and cleared everything but still no luck.  Is there some-
thing I have overlooked?  The unit has a Phoenix Tech bios vr. KE.M1.54.
I can get into the bios but I cannot find out what or how it is keeping
the bios locked.

If I am reading your post correctly, you are saying that you can see the BIOS on your computer, but it will not boot.
Where do you get the message that the hard drive is locked?
The situation that you are describing [seeing BIOS, but can't boot] would also apply if the hard drive had failed.
What information do you see in the BIOS about the hard drive?

Thanks for your reply.  I know the hard drive is locked because one of the POST statements says it is locked.  I also downloaded from the drive mfgr, Hitatchi, program that reads the drive statistics that the drive is locked.  The bios program also gives the info about the drive as it normally does.

Take a look at this link.

http://forums.actionfront.com/showthread.php?t=1003

According to that discussion, this is a firmware or hardware problem.
Check with Hitachi to see if they have a way to unlock the drive and if they have any firmware updates.
If you get it unlocked, make backups for all your data. :)
If they have an update for the firmware apply it. If the drive then locks itself again, I would just junk it since that would indicate a hardware problem.