That should work, though I imagine just uninstalling the catalyst control centre and reinstalling would work too as that is the part that's causing the problem. To be on the safe side I suggest you follow their advice as it's their software that caused the issue in the first place and they will know it's quirks. One thing that does surprise me is that the told you to reinstall .NET Framework v 2 rather than v3 as v3 is obviously more up to date, though there might be compatibility issue that we're unaware off. You may in the future want to install a program that requires v3 so if there is an issue with v3 it may may cause a problem when you update it. By the time that happens, your son would have probably moved onto another game anyway.
Rule No.1, Never install state of the art games on your work computer.
Rule No.2, Never let anyone else lose on your work PC - You've got more chance of getting your hands on my wallet than one of my computers!
