Hello Siborg.

Can you provide me with a link for this site? You may need to contact Microsoft about this, though.

Or you may be having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?

Whenever you have a problem with Firefox, whatever it is, you should make sure it's not coming from one of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in safe mode and select Disable all add-ons. If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See this article for information about troubleshooting extensions and theme. You can troubleshoot plugins the same way.

If you want support for one of your add-ons, you'll need to contact its author.

This - AlexaToolbar/alxf-1.54 - was added to the Firefox UserAgent string by something you installed, and it may be causing that problem with the Adcenter website.

http://en.wikipedia.org/wiki/User_Agent

type about:config in the URL bar and hit Enter If you see the warning, you can confirm that you want to access that page. Filter = general.useragent. Right-click the preferences that are bold, one line at a time, and select Reset, Then restart Firefox

Hi Morbus

this is the site that causes the problem

https://adcenter.microsoft.com/

I have since found if this is the first site I visit after booting up my PC it is ok, however, if I go back to it later I get the problem back.

Siborg, your browser is ridden with add-ons. Please read my post above.

Hi Morbus

I have tried it in safe mode with add ons disabled and I still have the same problem

Try creating a new temporary Firefox profile (managing profile). See if the new profile has the same problem.

If it does, you need to contact microsoft to know if their site is having problems.

Hi Morbus

It works in a new profile, thanks, but how do I find what is causing the problem?

I believe it has something to do with the user agent string. In your own profile, access about:config in your location bar (say you'll be careful, if the browsers asks you), search useragent and rightclick any bold entries (user set) and Reset them.

Then restart the browser.

It should work then.

Bear in mind that if some of your enabled add-ons is changing your useragent (possibly alexa toolbar), this issue may reappear.

Thanks but where do I find about:config in your location bar" ?

Where is my location bar?

The location bar is the place where you the address of the site you want to visit, and the place where you can see the address of the site you are currently seeing. You just need to enter about:config as an address, and Firefox will display an internal configuration page. If you want more info on the inner workings of the about: protocol and so on, just ask and I'll give you a few links. But first let's fix your problem.

Hi Morbus

Sorry I only know the location bar as the address bar.

Yes this has fixed the problem but after I disabled Alexia Tool Bar as well.

Well, I'm happy it's fixed.

The location bar is, indeed, known as address bar in Internet Explorer. Maybe that's where you know that name from :)

It's called Location bar in Firefox.

Thanks Morbus

I shall refer to the address bar as the location bar from now on

and yes this has fixed my problem thank you very much.