When I tried to sign in to Firefox today (11-1-15) using a username and password I created in September to install Firefox Mozilla as my browser on a new laptop with Windows 10, I am not allowed to sign in. So I asked Firefox to send me an e-mail to set up a new username and password and I didn't receive one. When I set up my account just now for this support forum, it said the e-mail address I planned to use ---which has @q.com as its tail end, was not valid. Even though the e-mail I used in September had @q.com on the end of it and Mozilla let me set up a browser on my new laptop with @q.com as part of my e-mail then, tonight it's telling me the address it accepted then is not valid. So I am not able to sign in to Mozilla Firefox using a username and password it accepted before. However and strangely enough, Firefox also let me go in to my "options" this evening and specify two pop ups as allowable. ?????