try the rollback if you had a previous Catalyst for that series, otherwise see if it will let you install from the CD without uninstalling the current driver( it might not).
You can also try the update driver button in properties, and put the CD in, but then Windows might tell you that you already have the best driver available because it sees the CD driver is older.
If you uninstall the current graphics driver and reboot, it is possible that Windows will again want to install a driver for you, so keep the CD in the drive when you reboot, hopefully it will look there first, or wait for you to tell it where to go...
If you can get the machine into the state where Display properties tells you the Adapter is unknown, then you can put whatever graphics driver you want on without interference.