hello, there's a known incompatibility with 0patch unfortunately which can cause firefox to crash on startup - in case you're using that security software, you can refer to their workaround: https://0patch.zendesk.com/hc/en-us/articles/360011227079-Mozilla-Firefox-73-can-crash-upon-launching-when-0patch-Agent-is-installed

Thank you very much!! It was really unpredictable, especially after the Windows update :) I thought Microsoft released bad patches once again. I'll do everything to fix this thanks to you!

Yes, everything is now working! Thank you for your help!