[tde-users] non-starting browsers

Now here's another puzzle. I don't know if it's related to my previous question about unwanted visitors in top, but I decided that I ought to start a new thread. I managed to get rid of those pesky unwelcome visitors, and imagined that I was on the way to having a machine that actually does what I want. All of a sudden, most of my browsers will not launch at all. I even went on a spree, and downloaded lots of different browsers, just to try them out (and to see if I could get anything to connect to the Internet). Thus far I have installed urf, surf-raw, netsurf, netsurf-gtk, midori, epiphany chromium, icecat, links2, lynx, elinks, vivaldi-snapshot, seamonkey and palemoon. Firefox is of course already installed by default. My regular browsers are icecat (to block everything that's unwanted) and palemoon (for when I am blocked from sites such as archive.org, etc.). I also use seamonkey for only one thing, which is a small blog that I don't really maintain much any more, but still like to check in. And I generally use vivaldi-snapshot for all my "business"-type stuff, where I must use a direct connection. Until now, this system worked just fine, both on my desktop computer and (since early December) on this laptop. Now, suddenly, only palemoon will load at all, and I am blocked from archive.org. The only thing that I have changed is to remove non-free and contrib from the lines in my sources.list, since networking has worked fine without any non-free software. And by the way, this is not, strictly speaking, off-topic, because it probably concerns tdenetworkmanager, or something like that. Everything else that I've tested, so far, works okay. I can connect to the internet, I can send and receive emails, I can download stuff. When I check top, these browsers don't even seem to load. It's not like they start loading then crash; they don't even show up on top. I am about to try an upgrade. And if that doesn't work, to add non-free and contrib to my sources ... but I would really rather not do that, since it seems like it ought to work without them. Help, please! Any suggestions are welcome. Even snide comments and jokes would be a relief. Bill