During AVG installation is some one application (mostly reported "S3Gsetup" or "3.0") listed many times as incompatible and AVG is asking for removing this application.
Please ignore this warning and continue with the AVG installation.
This situation is caused by registry record on place, where should not be (could only exist by mistake in installation of some application). And AVG installation is checking this key. In next AVG version should be this check (detection) removed.
You could check it by yourself by these steps:
- please check this registry key (menu Start -> Run -> enter "regedit" and confirm OK):