Try running Firefox in Diagnose Firefox issues using Troubleshoot Mode. If it functions properly in that configuration, then one of your add-ons is the culprit.

You can disable/remove PersonasRotator in Tools | Add-ons | Extensions, but running Firefox in Safe Mode will disable it anyway temporarily.

No image on that link you posted by the way.

I have never run Firefox in Safe Mode before and have no idea how to do that.

Is this a better location for the image? http://i251.photobucket.com/albums/gg314/franontheedge/Computer%20PC%20Problems/PersonasFault.jpg

I'm finding it hard to uderstand what to do with the addons since as I'm using Firefox 4 for the first time today, I'm still totally lost in this vastly different layout. I just went to "Addons Manager" and had to leave without doing anything since I couldn't understand it. Plus I couldn't find even the addons I had in Firefox3.6 never mind the personas rotator I tried adding when I got FF4.

I also can't find "Tools" either....

Okay I found safe mode for firefox, enabled that, disabling addons temporarily. Something in there might be to blame as when FF4 restarted4 windows opened, 3 of which were the larger version of the gallery image.

I closed that gallery image window - FF4 said was I sure I wanted to close 2 tabs - could only see one tab, nothing else visible, so I closed it anyway - 3 times.

It seems that doing this addon disabling disabled my tab groups - I love that feature by the way - I also found that most of my open tabs (the ones in the other groups) were no longer accesible, I know this because I could hear a YouTube video tutorial running, but could not find it. and I still can't find 'tools' anywhere.

You're using the new layout, so it's File | Options | Options (instead of 'Tools'). If you right click a blank part of the tab bar and click "Menu Bar" you get the old layout with the text links. I just prefer the latter that's all. Anyway....

Safe Mode is only intended to be a troubleshooting tool. If disabling add-ons enabled Firefox to function properly, then half the battle has been won.

What you now have to do is to start it in Safe Mode again, but this time, checkmark the option "Disable All Add-ons". Then click the button called "Make Changes and Restart".

Next, click the orange Firefox button and go to Add-ons. You'll get a screen which looks something like the one you see in the screenshot (from my own setup) except they will all be greyed out.

Where you see the "Disable" buttons to the right of each add-on, it will say "Enable" instead. What you have to do here is to click "Enable" one-at-a-time and check on your gallery site until the problem recurs. You'll know then that the previous add-on you re-enabled is the culprit. Laborious I know, but that's the only way of doing it I'm afraid.

Right, okay, I'll go through that... after dinner. Thanks.

Turns out it probably was the personas rotator, but not because there was anything wrong with it, just that it wanted me to install Personas Plus, and I hadn't done that yet. I did that, and then discovered that the speed with which the personas rotate is maddeningly distracting, plus it uses personas from flippin' everywhere, which obviously includes things I'd rather not see. and does not as I'd hoped use the personas I'd laboriously found and saved - that I did like. Also I'd rather it was once a day, or maybe once an hour, not everytime you click something.

I suppose there's nothing I can do about that is there?

Personas are stored in Add-ons | Appearance.

It says in the "More" link that you can change the default rotation of one per minute into whatever you wish. It's located in the Settings menu apparently.

Presumably, the one called "My favourites" will be in there somewhere as well (?)

Oh thanks very much, I didn't realise that the word 'More' was a link to the settings for this.

I'll try that out later. Much obliged to you. Oh and 'My Favourites' isn't one particular persona - it's where on the Personas site, you can select a number of personas and store them as your 'favourite' personas. And now that I know about the 'More' link, I see that if you are logged into the persona's site, the rotator will try to find 'My Favourites' that you have stored there, and it will use those instead of a lot of random ones. Which is exactly what I wanted.

Brilliant!