I use 3.6.8 and had the EXACT same problem. I also got the (Not Responding) when I used my web-based email account. Click on a message to open it in it's own window and it would freeze until ALL web-page content was loaded. Now I have no problems. To solve (for me,anyway), DISABLE every extension listed under add-ons. Restart. Go to Google images and check to see if that corrected the freezing problem. If so, ENABLE three (3) extensions at a time and restart then back to Google images. Keep doing this until you enable an extension and the freezing begins again. When you find the guilty party, disable it or uninstall it. For me the extension causing the problem was Flashblock. Because I had so many extensions it also gave me the opportunity to uninstall extensions I never or seldomly use. So maybe it was the ridding 6 extensions. I just know that whenever Flashblock was enabled, the problem returned. So in answer to questions about this, the problem was caused by one or more extensions. If disabling all extensions then trying Google images didn't work, you've got a problem that should be taken to Mozillazine. Good luck.