Firefox 3.6.12 locks up and stops responding when I attempt to load websites. There is no pattern to what type of websites are affected. It starts responding again after about ten seconds. Before it starts responding again, the Firefox tab in my taskbar appears to shrink briefly to what it looks like when I do not have Firefox running. If I go into options and disable JavaScript, I do not have this issue. I have tried clearing my cookies and my cache and this does not help. I am running windows 7. I do not have any add-ons installed. I did not change any settings before this started to happen.

EDIT: I went into the extensions and disabled AVG Safe Search and I no longer have the problem.