Password field is empty

I think the version is 4.3.1, I can’t get in to check if the webmistress updated it. I stay logged in since we’re working on two new sites. I rebooted my computer today for printer install, and now I can’t log in to either of my two wp sites. I’ve tried on Chrome and Firefox. I looked up old posts on this subject, and I deleted the past day’s cache, passwords, and cookies and plugins, as former posts indicated might make it work. On firefox, it’s the username that goes blank. I use lastpass to remember passwords, and i disabled that, and tried to type in the passwords. Nothing is working.