That is not possible. Older questions are archived automatically after six months and can no longer be modified (edited) and that is it.

TO: JSCHER 2000 When I clicked on my "settings" icon, the screen opened up and it is now all BLACK! How can I change it to white or a light blue? I changed my theme to CLASSIC WINDOWS on my homepage so that is OK for now.

You can change this pref on the about:config page from 3 to 2 to revert to the Firefox 94 behavior.

• layout.css.prefers-color-scheme.content-override [dark:0, light:1, system:2, browser:3]

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

See also these prefs:

• ui.systemUsesDarkTheme [light:0, dark:1, no-preference:2]
• browser.theme.content-theme content [dark:0, light:1, toolbar:2]
• browser.theme.toolbar-theme toolbar [dark:0, light:1, system:2]

Are you talking about "deleting old questions" or getting rid of the black screen on my settings screen? It looks very complicated.!!!

My last reply is about the black screen as it looks that you are satisfied with my reply about deleting old questions. It is rather complicated how Firefox decides to use a dark background and light text for webpage content and looks at various parts in the user interface (toolbars).