If the OS can boot then you can decrypt them as well as copy out the key.
BTW, if you fail, http://www.lostpassword.com has the app you need.
More at link -> http://support.microsoft.com/kb/241201
Given how many forget to do this, you begin to wonder if EFS should have even been fielded.
i have an old windows xp hardrive that i mistakenly encrypted a few years ago. I tried to tranfer the files using a usb to ide cable but it didnt work. i looked online and i says that my files are unrecoverable because i don't have the certificate/key. can i plug the old hard drive in another windows xp computer to unencrypt the files? I refuse to give up on getting these files, there are very important to me!