Finding Corrupted SAM file

Can someone help an old gal out? :wave I'm trying to do this for my 75 year old dad.

My Dad's computer had the error message: lsass.exe - Security Accounts Manager initialization failed - the handle is invalid. I installed a parallel installation of Window XP to get the pc to boot. My next step was to swap out the SAM file. However, after I installed the parallel installation (same partition but different folder), the copy and delete commands didn't work.

copy c:\windows\system32\config\sam c:\windows\tmp\sam.bak
delete c:\windows\system32\config\sam
copy c:\windows\repair\sam c:\windows\system32\config\sam

When I tried the windows folder, it says: cannot find path specified.
When I tried the new folder (winxp), it says: cannot access file because it's being used by another process.

I know I must being doing something wrong, I just don't know what. Any help you can give would be greatly appreciated! :confused