Hello, so I was doing something and then it started lagging. I closed Firefox and when I pressed it again it wouldn't start. It updated then it stopped working. I restarted my PC, clicked many times on Firefox logo and it wouldn't start. I got an error message in the top left corner that appeared for a milisecond. I took a video of it with my phone so I could read what was wrote there. It said "XML analysis error:entity undefined. Location:chrome://browser/content/browse Line number 53, column 1. (Sorry if it ain't the exact words, im translating because my Firefox is in french). There was also <windows id-"main-window"> under it. Don't tell me to open Firefox in safe mode, because that doesn't work either. When I hold shift, nothing happens. It doesn't ask me to go to safe mode. How do I fix this? Thanks