Are security certificates transfered by windows EZ transfer

I recently migrated from a Windows XP pc to a new PC with Windows Vista.
I used Windows EZ Transfer to "easily move..... user
accounts...settings....files etc".
Now I can not access the encrypted files on my external USB hard drive.
Where did EZ transfer put my security certificates? How do I regain access
to the encrypted data? Can my lost security keys be restored to the new PC
from a Windows One Care backup? Because I do not need to access the
encrypted data frequently I did not discover the problem until after my the
hard drive in my old pc was re-formatted.