Anybody? Please help.

Since this evening I have started having this problem too. If it continues I'll just go back to 3x or stop using ff altogether.

It's happening to me too, and it's affecting other programs I have running as well. I am not very happy with this.

I've been having the same issue. I'm actually using IE (ugh, I know, chrome wasn't installed on this specific computer) right now, and I'm having a better time using that than Chrome. This system, I was trying to search something in the URL and it froze on me. It's been frozen for an hour (I was searching to find if people had the same issue, and was too lazy to kill it)... and it makes me sad. I'm also having issues on my desktop system. When I open up PuTTy to get to a sql server and try switching between firefox and that, the thing hangs up. I *always* have to kill firefox after that. I have a dual-core 3.1ghz AMD Phenom II X2 550 Black, 8gig ddr3, a raid 1 config with two 1.5tb hds, and a 9800gt video card in that system... ohh and a 500w powersupply and Windows Ultimate 64bit

I had a similar problem when using Facebook in particular. I could not write a message due to the page freezing on me, very frustrating. Earlier on today I disabled the AVG Safe Search plug in (add on maybe) in the add on page. And since then I have not experienced any problems on Facebook or on the internet using Firefox 4. I had a similar thing happen when the new AVG 2011 was installed and disabled Link Scanner in the program itself because it was making pages slow and freeze. This problem for me at present began once AVG was enabled on Firefox 4. It wasn't compatible with the earlier version of Firefox but since two days ago it was awful. Hope this helps someone...........it worked for me!!

For me FF windows freeze in a way I cannot move the window around after switching tabs. Or the FF window moves sluggishly. No extensions/add-ons (only Skype but disabled). Sometimes can't move the window at all. I only have pages from msn.com and yahoo.com on the tabs. And various pages from FF support site. No other sites.

Almost unusable now.

Have to switch back to IE 9 now (which I don't want to!), until this window-freeze is resolved.

Just found out for me I turned off 'Use hardware acceleration when possible' and it seems the 'freeze on moving FF window' is gone.

https://support.mozilla.com/en-US/questions/800272?s=freeze+firefox+4+window&as=s

Still sluggish at times when moving a FF window. At least it's bearable.

I have 9500GT that supports DX10.

IE 9 is working fine w/ hw acceleration turned on watching YouTube HD videos -- pretty smooth, no sluggishness when moving windows.

Used this to test IE 9/FF 4: http://ie.microsoft.com/testdrive/Performance/FishBowl/Default.html

Result:

IE 9: 60fps.

FF 4 (hw acceleration OFF): 4fps

Going to use IE 9 for YouTube videos for now.

• • Someone needs to fix this FF4 feature (hw acceleration ON causing FF4 freeze on window--can't move around...).

This is for my case.

What happens with me is that Firefox ALWAYS stops working for a few seconds when I launch it, usually after two to three minutes of usage. It's not a big deal, just really annoying and it's made me switch back to Chrome. I'm running Windows Vista Business 32 bit with a 2.4 Ghz Core 2 Duo processor. It's not the computer honestly, because Chrome and Internet Explorer work perfectly.

I had reached the point where Firefox was freezing as soon as it launched. Recently, I had been getting the message the Firefox couldn't install the update completely. I realized finally that Firefox 4 was trying to update to Firefox 4.01. Using IE I downloaded Firefox 4.01 directly. After I installed it the freezing stopped.

It's REALLY ANOYING!!!!

I got a brand new super dupper powerfull PC with a brand new super dupper Windows 7 64bits ... but it got the same problem with Firefox 4. The new version ROCKS ... BUT IT FREEZE to death my pc! So slow... i got Firefox 4 running for 5 minutes and then ... BAM! the music stop, the mouse movements gets so (really) slow ... and gives me no choice but press the reset button ... no error log, no crash log ... nothing ... just FREEZES! Now i came back to my old but awesome to Firefox 3.6 and everything works fine... By the way ... I got Firefox 4 working in my asus notebook with same SO and NO problem ... that's the Anoying Thing!!! I really NEED Firefox 4 on this machine!!! ... so sad ... PLEASE GIVE US A SOLUTION !!!

@masterbip Using every font size and style there is won't get you or the developers any further in solving your and our problem. It's just annoying.

For me, crashes mostly happen when I'm working with the typo3 or wordpress backend, especially in saving processes. Already tried reinstalling it, no changes whatsoever. I'm both on a Windows 7, 64bit and a Mac OS X machine. Same problems, only seems to me that FF on a Mac freezes less frequently.

Anyway, it would be great if you could fix the freezing problems. I'm with Mozilla and Firefox since the beginning and by now I really rely on it. And I don't even want to start using IE as a substitute.

Thanks!

I tried 4.0 and 4.01.....both froze up my computer 6 times today. I've gone back to 3.6.10 and everything is okay. I'm sorry, 'cause I liked 4.1. Please, Mozilla, fix this and let us know when you have done so! PLEASE!

today firefox 4.1 just froze my pc 3 times -when this happen plugin-container.exe is stocked at 50% cpu usage- so none of the buttons working even my mouse cursor is gone... so all i can do is to press restart button....thios is really becoming annoying !!!!!!!!!!!!!!!!!!

I'm having the same problem. My OS is XP SP3 and this complete freezes my computer aswell, thought It was some virus but I am so relieved it ins't.

For me the freeze isn't 100% permanent, there are like 1 seconds ever 15 seconds where I can actually move my cursor or do anything, nonetheless it sucks.

yeah i have xp sp3 too and sometimes i can move for a short period the cursor but is useless ....what's strange is that the freezes are just random -for a whole week i had no problems then one day 3 freezes ,then after two days another freeze... anyway this is the Worst bug ever ever !

also have this since 4.x and still present in latest 7.x betas. seems related to javascript and/or flash

dropping FF now, switching to chrome. Hope FF will fix it some day.