Appearance of a black rectangle

hello

check the complementary modules of firefox/disable them....
and re-enable them gradually.

or reset firefox.

eventually, if windows is up to date, you update your software
with update checker?

--
a gardener who sabotages a lawn is a novice gardener.

Thank you for your response. I did as you indicated, but unfortunately, it hasn't improved.
When I open Firefox, my screen is now all black with a small white square before the Google homepage appears;

So you've deactivated your modules, you're up to date.....

Have you reset Firefox?
https://www.commentcamarche.net/faq/s/reinitialiser%20firefox

And what about an infection, what do you think?

Do you have any additional details?

Check here/
https://blog.developpez.com/cchatelain/p7336/informatique/que_faire_quand_firefox_ne_fonctionne_pl

You can uninstall it in safe mode with Revo Uninstaller
and pick it up again?
--
A gardener who sabotages a lawn is an amateur gardener.

I reset Firefox, scanned with my antivirus (there was an infection), cleaned up with Malwarebytes (11 infections), and since then everything is clean.

Thank you very much for your help

Good evening