I'm a little late in posting this but The Windows Servicing Guy has posted a supported workaround for torn state installations on Windows 7 SP1. I've tested it myself and can confirm that it works, with a caveat that you'll have to be sure to modify the package name used in the DISM command to suit your situation (see the comments below the post for hints on how to do this).
From what I can tell, this workaround gives you a less intrusive way of getting the ati driver folder rolled back to the appropriate version. It seems to take quite a bit longer but is definitely much better for those who are less confident and don't want to/feel comfortable with extracting the driver folder manually and going through the System Recovery console to put it in place.
