I had to uninstall 3.6.6 and go back to 3.5.x Not available in English apparently. 4.0 will be even worse as a memory hog, since it will be like Chrome, wich Vista gets along with even more poorly. I might actually have to go back to IE.... Here is the link

http://www.mozilla.com/en-US/firefox/all-older.html

I upgraded today and have the same problem. It's been getting so bad I'm willing to use MS explorer again. Fck you very much FF.

Same problem here! The last updates affect the whole system. If I open Avidemux, TVBrowser, Goldwave, etc., Firefox is going crazy and uses 100% of CPU. And also the whole time FF causes senseless CPU load...open a new tab, using search field, reload a webpage, even typing this message now. Thanks for nothing Mozilla...

I have had three crashes of FF in less than 5 minutes and I am not running anything flash or any video. This is on Windows XP on my work's desktop - an engineering machine.

I keep trying to do my job but windows crashes and I can't file my bug reports. *sigh*

I am tempted to download chrome or go back to IE 8 ! The horrors !

Same problem, not going to bother to go back to older version. Its good time to switch to other alternative !.

Same here. This new version is totally dead, LOTS of problems loading, and 80% of the time it freezes halfway - it appears as the loading is done in the status bar, but the page wasn't loaded.

After a few tries reloading the page it finally loads properly. I tried to change the proxy settings to "No Proxy" as someone suggested, for no avail - it only caused Firefox to crash FOUR times in a row right after I opened it.

I have been a huge supporter of Firefox for years, but the new versions are just becoming worse and worse, to a point that's becoming unbearable.

I've heard that the latest versions of Opera and Chrome are excellent. Time to change, I guess!

Same here.. Mac OSX 1.6.4. \\:

Question to all, do you all use Google docs when the problem occurs?

It seems I have the same problems with Chrome when using Google Docs.

Same here. Mac OSX 10.4.11

And I do use Google Docs but it happens even with them closed. Biggest issue is when typing out emails. It's about a sentence behind. It's unusable.

Tried re-install, didn't work. Have gone to Safari.

Arrgh.

I tried a clean install but it didn't help..

My second solution (FF 3.5.10 is my first solution, now in practice) is this:

http://www.opera.com/browser/download/

In the past, Opera failed my acid test (accessing the horrendous oil spill called microsoft hotmail); this time around (Opera 10.60) it seems to work very well so far.

It's also *shockingly* fast on my ancient 650 MHz W2K/SP4 machine.

The mechanism to block images (I use to get rid of advertising garbage) is not same as firefox, and I'm not used to it yet, but I'll keep with Opera for a while...

I could not work around 3.6.6 hanging, using all of my CPU and I hate how chrome fills my computer with bulky crap, so I now use opera as default and 4 beta to use my extensive bookmarks so I can put them in opera. Neither do page saver, so for us who don't always have a printer handy, it cuts my productivity. I hope FF is listening, not all of us have fast connections or the latest computers. Some of us live in mountains and use (gasp) Vista..

I am about to dump FF, this is horrible for safari. Is there a fix coming?

Next apps which is driving FF crazy: Media Player Classic, Cut Assistent, FFDShow -> 100% CPU load. But I ask myself, why do all these apps affect a web browser (or does FF affect these apps)? Is this a memory bug? FF has an extremely low memory usage (about 140MB, normal average is 250MB) when opening one of these apps and running mad at 100%. Close them and FF is running fine...

Having the same problem when using Google Docs, after upgrading to 3.6.6

fire fox sucks badly

Not a FF user, but had similar problems in Chrome after latest Adobe Flash Player update. Try this: disable all unnecessary plugins (especially Java Deployment Toolkit), worked for me.

I wish that Mozilla would at least let us know if their going to fix the problem or not.

Firefox 3.6.6 sucks, it's extremely pathetic how slow it is.

They need to fix this very soon, or else I'm switching to a different browser.

WTF did they do to it why dose it hang my computer now. why is it unusable hello Mozilla please fix it.

Since 3.6.6 update, FF is running so slowly. I'm on Vista, and haven't changed any plug-ins etc. Very very annoying - so much so that I'm even considering going back to the dark side (IE).