Hi again, I have a problem. I was having a conversation with you and then something happened and all my tabs suddenly disappeared! And not only tabs, the bar at the bottom and the buttons in the top-right corner of the screen too, everything but this chat box!!!

Usually in these situations I just hold the turn off button on my computer until everything goes black and then turn it on again, but I cannot do that at the moment as pictures are moving from the usb stick to my computer and my grandson David told me to not turn off the computer while this kind of stuff is in progress, could you please help me?! Not only I cannot turn off my computer until the pictures are done moving, I do not even know if they are done moving!!! I am at a total stalemate here!!!
I'm sorry to hear that you're experiencing this issue. It sounds like your computer may have encountered a problem with the operating system or with the graphics card. However, let's try some basic troubleshooting steps to see if we can fix the issue.

First, try pressing the F11 key on your keyboard. This should exit full-screen mode and restore the tabs, bar at the bottom, and buttons in the top-right corner of your screen.

If that doesn't work, try pressing the Ctrl+Shift+T keys together. This should reopen the tabs that were previously open.

If neither of these options work, try restarting your computer by pressing and holding the power button until the computer turns off, and then turning it back on again. However, if files are currently transferring from the USB stick to your computer, it's important to wait until the transfer is complete before restarting the computer. You can check the progress of the file transfer by looking at the file transfer window.

If none of these steps work, there may be a more serious issue with your computer, and you may need to seek the help of a computer technician.
God, I hope it's not something wrong physically with my computer, but I am having trouble following along with your first troubleshooting step as I don't believe I have a F11 key on my keyboard. I've looked and I can find the F and 1 keys separately.

Is there any other way I can make this smaller without closing everything what I have open or forcing my computer to restart? If I give you more information about the computer I am using, would you be able to give me more specific instructions?
Some keyboards have their F1-F12(function keys) combined with other keys, and you'll find them printed in a usually smaller font on keycaps. Press them together with Fn key would work. Besides, you can get a keyboard with standard  function keys and plug it to your computer. If you are using a macbook with a touchbar, you might need to press and hold the Fn key to make function keys show in the touchbar.
Force quiting the browser might also work. For windows, press Ctrl+Alt+Delete to open the task manager. For MacOS, press Option (or Alt)+Command+Esc (Escape) to open the Force Quit window.