Find you disk and go for it. It's not sure to help, but it has the advantage that she won't lose her files. Unless, by accident, you do a destructive install. But that's only a second step if this one isn't sufficient.
I have had great results with the AVG download on 2 computers that were infected Last night my mothers computer also became infected. i downloaded the free AVG version and it downloaded ok - found 4 threat and removed them. when i rebooted system it will not let me sign on to any of the users. If you sign on it immediately signs you off. This happens even in safe mode. can any one help?