Hi please start here https://support.mozilla.org/en-US/kb/firefox-keeps-crashing-startup https://support.mozilla.org/en-US/kb/avoid-crashes-tips-and-tricks https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Keep a copy of the logs. Also could you provide as much description as possible if need to come back. What are you doing when it crashes, ect.. did you follow the above and what where the results. If malware is found and can not be cleaned or if still experiencing issues that might have been caused by malware it might be better to follow up with expert malware removal forums. Please let us know if this helps solve your issue.