• uninstalling

Can you start Firefox in its own Safe Mode? Hold Shift and start Firefox: https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode#w_how-to-start-firefox-in-safe-mode. You could at least make backups from Safe Mode. I've heard of trouble with Kaspersky's anti-banner functionality, so you could try turning off the browser protection components in Kaspersky to see if it can coexist with Firefox on your system or not.

If you need to back things up without starting Firefox, navigate to your profile folder, http://kb.mozillazine.org/Profile_folder_-_Firefox#Windows, and copy that. It should contain everything down to your bookmark history backups and extension settings.

Thank you so much for those tips! It does appear, however, that the problem is definitely with the Kaspersky software. Chrome soon stopped working as well. The only way I was able to get my browser functionality back was to uninstall Kaspersky. Fortunately, the Kaspersky uninstall tool worked this time and after I rebooted I was able to use Chrome and Firefox.

I can't figure out what the issue could be though, but the problem is on Kasperky's end evidently.

Glad it helped!

I'm afraid Kaspersky just likes behaving badly, their recent track record is messy. I would consider alternative software.

I've recommended Bitdefender and ESET with good results. Both are light to run on a system, good for detection and prevention, and haven't caused issues with other software so far as I know. Sometimes you may need to reintroduce their certificates into Firefox (they may get lost when Firefox updates) to allow secure connection scanning, but that's it; in Bitdefender you Repair the installation, in ESET there's a button for it.

Both offer free trials of the full software before you buy.

Of the free options, I would recommend Microsoft Security Essentials if you're on Windows. It comes integrated with Windows 8 and up I hear (I'm on Seven), and it's not terrible against ordinary threats. You can get it for Windows 7 and Vista here: http://windows.microsoft.com/en-US/windows/security-essentials-download.

AVG, Avira, and Avast are also free, but AVG spies on you, installs junk, and may refuse to uninstall properly. Avira includes junk in the installer but does not install it forcefully AFAIK. Avast has had compatibility issues with other software.

I gladly pay for my security software to ensure their only financial motivation is my protection and user experience.

Thanks for the advice. I think I'm going to go with Norton. Kaspersky was supposed to email me a support tool that would help them diagnose the issue, but they never sent it. BitDefender was using a lot of memory and wouldn't give me notifications. I also can't get their techs to respond to emails. Avira crashes. Avast didn't have the functionality I was looking for. ESET is good, but I didn't know they let you try out the software first. That may work better than Norton.

Norton will blackmail you with licences: once your old one is up, ALL protection, not just updates, ceases immediately, and all access to basic functions is denied. I found this out to my dismay after a holiday - that's when I switched to BD. Ghost (backup software) was equally frustrating to deal with (now on NovaBACKUP).

Norton's performance improved a lot some years back (that's why I gave them another shot), but they still employ poorly made plugins last I checked, and their AV will rule your system with an iron fist - and not in the blocks-all-threats kind of way, it's more like I-can't-let-you-do-that-Dave. Can be very frustrating.

I've had a pleasant experience on the BD support forums, but if yours has been poor, no reason to throw your money at them.

BD memory use has been discussed on the BD forums, and the devs made a fair point: 200-300 MB is not an unreasonable amount of RAM on modern hardware (8 GB pretty standard, not a big chunk off of 4 GB either), as that allows the software to reduce its dependency on slowly-reading mass storage devices. Overall performance benefits as a result.

Just consider all that needs to be scanned when even browsers and their plugins now rake in RAM by the gigabyte. The more programs you run and the more data they access (and the more protection you activate), the larger the memory impact.

Dunno about the notifications; I've had just the right amount, it's been pleasant not seeing a pop-up for every little thing the AV does (I'm looking at you, F-Secure).