Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance). *Do NOT click the Reset button on the Safe Mode start window. *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes Clear the cache and cookies only from websites that cause problems. "Clear the Cache": *Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now" "Remove Cookies" from sites causing problems: *Firefox/Tools > Options > Privacy > Cookies: "Show Cookies"

look for the alternative plugin for playing and download