It won't launch at all, even in safe mode (shift click on Firefox icon). When I open process explorer it shows Werfault.exe only , firefox.exe won't even appear. This happens only after updating Firefox to 57 version. I cleaned sustem with ccleaner, tried starting Firefox directly from exe - didn't helped. Downgrading to 56 or lower versions solves this problem, it only happens on version 57 either 32 bit or 64 bit.