Upgrade your browser to Firefox 8 and check

• getfirefox.com

Hi Swarnava,

many thanks for your reply, I have tried several times to upgrade to Firefox 8 and at the end of the setup it tells me it was successful, but go back Firefox website and it tells me I'm running an older version

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9.2.17) Gecko/20110420 Firefox/3.6.17 ( .NET CLR 3.5.30729; .NET4.0C) FBSMTWB

Your UserAgent string in Firefox is messed up by another program that you installed. http://en.wikipedia.org/wiki/User_Agent

type about:config in the URL bar and hit Enter
If you see the warning, you can confirm that you want to access that page.
Filter = general.useragent.
Right-click that preference and select Reset
Then restart Firefox

fixed my error

Hi the-edmeister,

I have followed your instructions, but unfortunately I have no general.useragent.extra.firefox I'm assuming I wasn't supposed to add the line

These are the list under general

general.autoScroll;true general.config.obscure_value;13 general.skins.selectedSkin;classic/1.0 general.smoothScroll;false general.useragent.compatMode.firefox;false general.useragent.extra.microsoftdotnet;( .NET CLR 3.5.30729; .NET4.0C) general.useragent.locale;en-US general.useragent.override;Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9.2.17) Gecko/20110420 Firefox/3.6.17 ( .NET CLR 3.5.30729; .NET4.0C) FBSMTWB general.warnOnAboutConfig;true

I am sorry, I posted the wrong clipping from my file.

general.useragent. - is what you need to look for. Reset the prefs that are bold.

Hi, Many thanks, resetting the 2 bold lines

• microsoftdotnet & * override

has allowed me to upgrade to Firefox 8

However this has not resolved my previous issue of 'not responding'

I did note that there were a lot of highlight lines in the config all the AVG, all CT2786678 and others, should I reset these?

No, don't reset any other preferences, the goal was to fix the "locked" user agent string and allow it to get set properly by Firefox as new versions of Firefox are installed. The Firefox 4+ versions don't allow programs or add-ons to change the general.useragent. prefs as was allow in 3.6 and earlier versions.

As far as problems with AVG 2012 and Firefox, I have no ideas. I haven't used AVG since 2008 when AVG came out with a new version and started causing problems for me with Firefox. I switched to Avira Anti-Vir free edition and find it to cause no problems with Firefox.
The only thing I can suggest is to disable the AVG extensions that AVG installs for Firefox and see if that not responding goes away.

CT2786678 prefs may have been added by a Conduit Toolbar (spyware?).

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes

Hi All,

Thanks everyone for their advice I did as you suggest cor-el, tried safe mode later reset to default, little helped. However this morning, not sure if any upgrades have been made to either Firefox or AVG but everything seems to be working fine again. The main problem seem to be if videos were embedded into web pages, YouTube just didn't work, nor embedded video links in forums. Now everything works fine. Many thanks again for all the assistance and this is why I prefer to use Firefox a superior product and with genuine backup support.

Cheers JD