I-Firefox Isithangami Sokwesekwa

I have been using Firefox on my Mac for years with no problems. Recently, however, I have been having trouble running YouTube. I get to the correct page for the video I want but the video itself does not show up, just the background for the page. Any idea what I might have done to create this problem?

So for some reason I have two versions of Firefox on my computer (Windows 64 bit), I am logged in and using one of them, and the other is just there. I could log in there but I don't want to, I just want to get rid of it. Links from Telegram open in it, creating a second Firefox window instead of opening in another tab in the already open Firefox window, which is very inconvenient. The windows list of programs which can be uninstalled only has one Firefox (I've tried deleting and reinstalling, it doesn't help). But when I try to choose a default browser I get 2 icons to choose from which look the same (see screenshot). What the heck? How do I manage this!

I'm currently on a very old version of Firefox simply because the new versions, each time I try the latest versions, seem to not have the function the old one has. Remembering the websites I put into the address bar. The version I am currently using did have a issue with shuffling the order of the sites based on 'use' but setting Firefox to Private mode kept the websites locked in order and did not make them shuffle if one was clicked more often than another. Is this something I can do on the current version because I tried and looked for a way to do this recently but I kept getting 'autofill' results from google when I just want to be in Private mode, have the websites I frequent be the only ones listed when I click the address bar and not have them shuffle or have any other website I'd type into the bar not add itself to the list. If this is or isn't possible let me know.

Hello, I recently find products added to check out from various sites to purchase. I use all my pcs and other devices. They are all password protected. No one uses my devices. I think some one got my account. I changed the password. Can you help me about this topic Kind regards sami