Can you explain more please? When you go to http://www.dell.com/ what happens? Do you get an error page? Nothing? Do you have trouble anywhere else?

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

I get this (and I've done all that)

The page isn't redirecting properly

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

   This problem can sometimes be caused by disabling or refusing to accept cookies.

and I can get to the site perfectly with any other browser.

Did you try the link I posted?

http://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can