If you didn't format the machine and install from read-only media, you probably didn't help them all that much.
Industry best practice is to format and re-install:
Why do I have to format and reinstall Windows after my computer is infected with a virus?
Yup. Had to do complete re-installs. I recovered what data of theirs I could, but most of it couldn't be recovered (backed up reliably to DVD/CD).
They were devastated to say the least.