Hello boeland, go to about:config and be sure you have both, browser.cache.memory.enable & browser.cache.disk.enable set up TRUE (the default), then set browser.cache.check_doc_frequency to 1 (right-click, modify, set 1). Check it again, it is ok ?

thank you

Ideato, Thanks for your reply and help. The first two were already enabled as the default. The browser.cache.check_doc_frequency was set to 3. I set it to 1 but it didn't help the problem. When writing the URL it still brings up the old (non-existant) web page. I know it is non-existant because the person in charge of the site told me so and actually, as mentioned before, the other computers open the new web page. This is somewhat maddening.

Except the cache and history did you delete the specific cookie also ?

Yes, I deleted the specific cookie and cleared the cache after doing the steps you mentioned earlier but to no avail.

You can try to reset (power off/on) the router.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make a note of those passwords and bookmarks.

You can't recover from this 'forget' unless you have a backup of the affected files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.

cor-el, Thanks for your suggestion but it didn't work. I still get the non-existant web page.

in which regards is the website expired/changed? - maybe you can try to flush the dns cache on the one computer affected...

www.ghacks.net/2011/03/13/how-to-flush-the-dns-cache-in-windows/

philipp,

Good suggestion! That was it. I changed the DNS and it resolved the problem. Thank you very much for your help!