No answers I am afraid, just some general comments.

The problem may relate to your system or security software rather than being directly a Firefox problem, because another browser is also crashing.

Try disabling the security software, (maybe whilst not connected to the internet, so as to reduce any risk), if that does not help consider temporarily uninstalling the security software.

Note some security software is likely to view an updated program such as a Firefox update, as new software, and may require permisions to be reset.

Thanks - I have disabled the security programmes, but this made no difference.

Changed to the Guest Account and could access IE from there, but not Firefox. Firefox did not crash though, but immediately went to "Not Responding" and did not recover from that.

I have also uninstalled and re-installed Firefox 5, but this made no difference. Ran virus scans - found nothing with Kasperksy Pure

Should I try the previous version of Firefox - Restore to previous PC state (I dont like to do that)?

I have the same problem. FF5 just freezes and soon the "not responding" appears behind the header.

Ive tried in safemode and it works a little better/longer but the problem is still there.

Sometimes it happens with one tab open and sometimes I can have several tabs open before this phenomenon occurs. Its totally random. Ive deactivated addons and so on but nothing has helped.

And it all started happening after the last upgrade that downloaded itself yesterday.

I've even tried to uninstall and reinstall FF again with NO progress because the "7-zip access denied"-CRAP wont let me install it.

Elnavan,
Restore to previous PC state may indeed become necessary; but that is off topic, in so far as that is dealing with your PC problems, not your Firefox problems.

The likely cause of such messages is lack of disk space, how much free space have you got on your hard drive in GBytes and as a % of disk space ?
and what is the total size of the drive ?
From your earlier comments I assume you have seen:

• Fix the "Could not initialize the application's security component" error message
• it may also be worth looking at http://kb.mozillazine.org/Could_not_initialize_the_browser_security_component

If you have the disk space then using a new profile should solve your problem. Please try creating and using a new profile. see

• http://kb.mozillazine.org/Profile_manager#Creating_a_new_profile

Digressing slightly as far as Firefox is concerned it is relatively easy to for instance install and run multiple versions. There is no need to regress to previous system states to sort out firefox problems. If you downgrade from Firefox 5 however the official suggestions are that you go to Firefox 3.6 because Firefox 4 is now unsupported, and not offered as a standard downloadable installation. It may be worth considering a new profile, or even a clean reinstall of Firefox, but in your situation I would be looking for the other causes and problems first of all.

Whilst understandably you are trying to troubleshoot Firefox problems, I suspect the problem is deeper than that, otherwise IE would run without crashing ?. I am not a Window 7 user but surely that has its own diagnostics for problems, such as an event viewer http://windows.microsoft.com/en-US/windows7/Open-Event-Viewer.

Relating to Firefox troubleshooting see

• safe mode
• basic troubleshooting
• http://kb.mozillazine.org/Standard_diagnostic_%28Firefox%29 includes clean reinstall instructions

Salle,

You probably have a different problem. Are you seeing the message:

"Could not initialise the application's security component"

If you see that message read my comments otherwise it is probably better to start your own thread by asking a separate question.

THANKs - creating a new profile did solve the problem.

I will still try to find the mistake on the other profile - as you suggest look at some of the Windows 7 diagnostics. My W7 itself has been somewhat unstable in the past with some basic routine activities - but that is another problem.

Glad to have helped. I hope you sort out the new profile without problems. Make sure you back up your bookmarks as soon as possible, and certainly before considering deleting any old profile.

If you have problems with bookmarks post back again. You may wish to look at

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-...
• backing up and restoring bookmarks

Same crash problem for me. I rolled back to two weeks earlier; no luck. Uninstalled 5.0 and put 4.0 back in; no luck. Reinstalled 5.0, same thing - Firefox exits after a minute or two. I created a new profile, same results.

FYI, I am on Win7, 64-bit machine

YammaDharma,
I think you would do better to start your own thread.