hi bro,its quite simple just follow these steps, 1. Click the Firefox menu in the toolbar i.e., a three horizontal lines symbol at top right corner. 2.Now choose preferences in the menu 3.Now click on privacy&security option 4.Now by scrolling down you find a segment named "Logins and passwords" 5.Now untick the “Ask to save logins and passwords for websites”.(or) if you want to do this only for particular sites you can click on exceptions options wihout unticking and there you can give the site adress where yo don't want mozilla to ask save password

need any more help I'm there :)

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems