Try to update your Firefox, sometimes there are bugs that are fixed in a new release. You go to the Firefox button on the top and click it, then Help and About Firefox.

hello, i can't even open firefox now. it says the application is already running but it's not open

I tried to scan my computer with Symantec Antivirus, but it doesn'respond

If it says it's open it may be running in the background. Since you are using Win 7 you're going to open Task Manager by hitting Ctrl+Alt+Delete, then "Start Task Manager" open the "Processes" tab and look down the list for any that say "firefox.exe..." if you see one click it and then hit the button that says "End Process".

I can't manage to solve it. I tried to read all the Help page about the problem and to solve but it doesn't work. Firefox (and also Internet Explorer) still clash when I try to open certain tabs

Hello?

I have just updates my firefox form www.firefox.com however when I try to log into my gmail account it crashes. any help is much appreciated

Try to update your plugins Plugin Check that website will check for out of date plug ins.

I am having the same problem with Firefox and Gmail. I am using Firefox v7.0.1 and, at this time of posting, everything is up-to-date.

You said everything is up to date I just want to put a list of things to make sure everything is up to date because some of these things you look at and think what does that have to do with Firefox so check that list, then I have the next thing to try below the updates. The updates to check for:

• Firefox
• Plugins
• Windows
• Graphics Driver
• Internet Security

Have you checked your system for viruses/spyware? The following programs can be downloaded to do a check free of charge:

• Malwarebytes
• SuperAntispyware

Personally I am a fan of Malwarebytes. This article may help.