Re: uninstalling AVG 2011
if AVG is correctly installed, it should automatically disable Windows Defender from starting as this is another (default Windows) anti-virus protection. It is not recommended to enable Windows Defender again.
The Windows Security Centre should report only AVG Anti-Virus and Anti-Spyware components as active/not active/outdated. There should not be mentioned Windows Defender at all.
What is the current situation?