You could try running Firefox in Diagnose Firefox issues using Troubleshoot Mode to see if that influences the way it runs.

If it performs correctly, then one of your add-ons is the culprit.

Thanks for the response! I just tried what you suggested and it is still freezing. It has now progressed to any website freezing/hanging instead of just when multiple tabs are open. If I let it sit for a few minutes it will work but if I clink a link or go to a new page it will freeze again.

Try doing a cold boot. So shutdown the PC and remove the power cord from the back of the machine. Wait a full two minutes before you power on again.

Okay I tried that, but it still isn't working

Create a new profile as a test to check if your current profile is causing the problems.

See:

• Basic Troubleshooting: Make a new profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins"

If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files)

See http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I made a new profile, then changed the homepages to what it was with my default profile, and it still seems to be freezing

This is actually a documented issue. See Hang after prolonged use

You could try using the option suggested there i.e. reduce your homepage to a single site, but close only the pages you don't want to reload in the next session.

The problem is that it isn't freezing after prolonged use. It happens when I turn on the computer and open Firefox. Even when reducing the homepage to one site it still freezes. It seems to have trouble loading every page; it will half load it, then hang for a few minutes, then be ready to go..but as soon as a link is clicked or new page is loaded it hangs again. Thanks for all your help, by the way

Try clearing the cache. To do that, go to Tools | Clear Recent History.

Next, click the arrow and checkmark Cache only. Then in the dropdown menu at the top, choose Everything and then click Clear Now. The "Everything" setting will delete your browsing history completely, so be aware of that.

Still no luck. It seems only have major trouble when loading pages with lots of flash- ads and such. Perhaps this is the problem?

Could be. I suggest installing this Add-on: Adblock Plus

When you install it, subscribe to Easylist which currently filters 11,000 Ad sites.

Also worthwhile is to subscribe to Malware Domains which you'll find at the foot of this page: Adblock Plus Subscriptions

Add any of the others you like the look of too. It definitely speeds up surfing if FF is not waiting to load ads all the time.

Downloaded Adblock..still isn't working. Not sure what other info I can give...

Is this problem with it freezing restricted to Firefox, or does it happen with IE as well?

IE is running smoothly, Firefox seems to be the problem.

Can you go to Tools | Options | Advanced | Network (tab) and then click the Settings (button). Are you trying to connect via a Proxy server by any chance?

The button is checked that says 'use system proxy settings'

OK, click the one at the top called "No Proxy" and see if that makes any difference.

Nope, still freezing. An alert popped up on my computer today, I took a screenshot of what it told me: http://i.imgur.com/wWEWu.png

Which leads me to this site: http://support.mozilla.com/en-US/kb/Plugin%20crash%20reports As far as I know, I have the updated flash..

Are you blocking plugin_container.exe with your firewall by any chance?

It works like a kind of sandbox by isolating plugins which crash so that you can continue working with Firefox. If it doesn't have Internet access, some sites won't work.

You can check whether it is working properly by going to this page: Adobe Global Security Settings Manager If you can't see the control panel, then plugin_container.exe is probably being blocked by your firewall.

I can see it and click around on it, actually..