Can you attach a screenshot? *https://en.wikipedia.org/wiki/Screenshot *https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem *use a compressed image type like PNG or JPG to save the screenshot *make sure you do not exceed the maximum size of 1 MB ---- You can check for recently installed suspicious or unknown extensions. Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> 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 -> Appearance *Do NOT click the "Refresh Firefox" button on the Safe Mode start window *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes See also: *https://support.mozilla.org/kb/disable-or-remove-add-ons *https://support.mozilla.org/kb/uninstalling-toolbars You can check in "Windows Control Panel > Programs" for recently installed programs to see if any suspicious software shows up. *Control Panel > Programs > Programs and Features > Uninstall or change a program *click the Installed column to sort by this heading