Firefox has its own "safe mode" might want to try it this will tell you if an add-on is causing a problem here is how to access safe mode in firefox: Click start>Programs> now look for (Mozilla) put your mouse over mozila to the right in a drop down thing click firefox (safe mode) see if will start this way.

I get the warning also that the certificate is expired or has errors or something like that each time I go to any page here to log in, I have been just clicking on continue on anyway and log in. I have found if I am logging in on a lot of different devices I will have to log in more often, I use my tablets, phone and pc regularly, at times I get the log in requirement on one, it also happens with other sites, my guess is their detection sees a new device or browser and want to make sure I really am who I say I am.

Never mind.....I went to Firefox troubleshooting, and I think it's fixed. If not, I'll be back. For some reason, it wasn't selecting the right printer name. I had to select it manually, then it was okay. I don't know why this would happen, as every place else was selecting the one I have marked as the default printer. Shirley

And old trick in the early days of PCs (8088, 286 perhaps) was to power the thing down, unplug it from the wall and wait several seconds and then power it up. I've once resolved a problem within the last couple of years reverting back to that obsolete method. (I've an old TV that must be unplugged from the wall ever time it is turned on. This must have something to do with a chip inside.) Today GW gave me a couple of blank screens and I had to reload. These things happen occasionally but should not happen day after day.