Please post the exact build number of AVG, you can find that by opening AVG's interface.

AVG Internet Security 2011 works fine with FF4.0.1

What does not work with Firefox is "AVG Safe Search" extension that AVG installs. You can disable the extension, but it would be better to reinstall AVG without the "Link Scanner Component". For details including links at Grisoft, see

  http://kb.mozillazine.org/Problematic_extensions

Thanks. Have had several other detailed descriptions, and am going to try them. However, you may have another possible answer to the question so my version of AVG is 10.0.1382. The reason for what might seem to be 'over cautious' is that 2 years ago I had my identy stolen, and I never want that to happen again. So please send along whatever advice you might have. And thanks again.

Thanks. Sounds encouraging. Will go ahead and install FF4. If I wind up with insurmountable problems I can always go back to MS Internet Explorer!!

Thanks for the suggestion. I now have 3 possibilities. At least one of them must work, (unless I fall victim to Murphy's Law!!) Thanks again