Question : Problem: Files copied to new HD encrypted.

I upgraded my Motherboard from Celeron 533 to P3 1000 and Hard drive 80 GB NTFS to 250 GB NTFS.  Old system Windows 2000 Pro, New systems windows 2000 Pro and Windows XP Pro.  80% of my files are now encrypted and I can not access them.  I copied all of the old files to a folder to clean out at a later date and reloaded the OS as a clean install.  I also reloaded all of my software as a clean install.  One difference is I changed The computer name and user name.  How do I unencrypt these files so i can access them.  The most wanted are of my daughter's wedding and other family pictures I have taken with a digital camera and have no negs.    

Answer : Problem: Files copied to new HD encrypted.

>>I get an error message. <<
As in... what error message?
Do you still have the encryption keys? If not, then you're lost, it'll take thousends of years with that computer to break EFS encryption (not meant as a joke)

If you still have them, here is a tool that should be able to help you:

Advanced EFS Data Recovery 1.30

Is a program to recover/decrypt files encrypted on NTFS (EFS) partitions created in Windows 2000 and Windows XP.
Files are being decrypted even in a case when the system is not bootable and so you cannot log on,
and/or some encryption keys have been tampered. AEFSDR effectively decrypts the files protected under
Windows XP (including Service Pack 1) and all versions of Windows 2000 (including Service Packs 1/2/3/4).
http://www.softempire.com/advanced-efs-data-recovery.html

If you're not sure if you still have them, try the tool (the trial will be able to tell you if the files are recoverable)

LucF