New with no Internet

Hi. My name is Sue and this is my first time to be on such a site. I don't know my way around and I don't have time to find the mannerly way of things because I'm losing Internet every 30 seconds. It can take me half an hour to post a one-sentence tweet on Twitter because the Internet drops off every 30 or less second after I "diagnose" it to get it back on. Over and over and over. That's how I found your site. I searched "my Internet keeps turning off..." Thirty seconds is not a lot of time to peruse a new place and adapt to the culture enough to make friends and ask for help so... Actually - It looks like this bout is over. I've had Internet long enough to type this far.
So! I came to ask for help with my computer that regularly goes through hours' long spells of dropping Internet every 30 seconds and that quit playing videos a couple of months ago. All this happened without me doing anything to cause it. I really don't do much at all anymore. Mostly I just play Zoo Tycoon but I also visit Fox News, Twitter and Proton Mail daily. I do all this with Frasier playing on Hulu for white noise. I'm 64 and live in PA.
I have a cheap 6-year-old PC that has been nothing but a series of problems since I bought it. I've never owned a laptop. My previous computer, which I used 24/7 and dug around in for almost twenty years was much more reliable. I still use the printer I bought with it although the scan function mysteriously stopped working after I bought this computer. I think I use Windows 10 but I'm not sure. Whatever they've forced me to use - that's what I'm using because they refuse to allow Windows 7 to work any longer.
Since my Internet has stayed this long, I'm going to go do a few things that need doing and then I'll come back and look around to see if I can find something that will help me out and if I can't, I'll find out how to ask for help.
Thank you so much for your very welcoming site!

Thank you, Bruce! Hi!
The hardest part of this was finding my way back here! lol

Oh. What's a PSU?

Hi Peter! I forgot to put in my 'About Me' post that I work overnights (1:30 AM - noon) and sleep during the day so it's not that I'm not gratefully paying attention - it's that I'm sleeping when the rest of you are being productive. I'm awake now, though, and it's my day off so I'm headed for a flashlight and I'm crawling under my desk to peek behind my tower.
I should tell you that I rent a decrepit, dark basement and do not have cable. I use my landlord's cable (with his knowledge & permission) through my WiFi, which from what you said about my Bluetooth, appears to not be working? I have two WiFi things plugged into my tower. My computer is always turtle-slow but this dropping the Internet every 30 seconds is new for the last three weeks.

Okay:
Yes - my computer is a Dell Insprion 3847. Well, my tower is. My monitor is HP and my keyboard is the cheapest one they had at Best Buy.
The router is upstairs in landlord's living quarters. I can only get Internet through WiFi. I keep computer on a desk almost directly below where his router sits beside his TV up there. I have thought about drilling a little hole in my ceiling/his baseboard and hooking directly into modem but he cleans house regularly and I think he'd discover it pretty quickly. I understand not being plugged in to the router is a huge problem but I don't understand why.
My daughter does not have any problems using the Internet with her laptop or her phone. My PC is sturdier and has more components so I think it should be more stable with WiFi.

Yep. It hovers on two bars 90% of the time. It'll light-up all the bars for a few seconds after (re)connecting or diagnosing but then it drops as soon as I open a tab on Internet. The other 10% of time it's either one bar or three bars. Right now it's 2.

Computer also has built-in WiFi but it's never worked as far as I know. That's why I got the ASUS usb-ac53 Nano usb Wi-Fi Adapter.
Then a co-worker's kid who helped some problems last year bought another one because he didn't know there was already one plugged so I have two of them now.

Well. This is embarrassing. I was looking through my drawer for the name of the other Wi-Fi usb adapter (TP-Link, btw) and I found Both adapters in the drawer. I checked back of tower and there is No adapter plugged into it. I cannot conceive of when or why I would remove them. It doesn't make any sense whatsoever. Oh... Maybe Dell told me to remove them when I paid them to remote access computer about a year ago because running Windows 7 made it go bonkers and I couldn't do anything with it. Maybe they had me remove them so Dell could get the built-in Dell Wi-Fi to work? Want me to plug one of them in now?

My daughter gets on Internet with phone and laptop like I do - automatically. No hot spot or data usage. Yes - we have the password.
I'm going to put the Wi-Fi usb in its slot now except...
Which slot? One time someone said I had something plugged into one slot and it should have been plugged into a different slot. Might have been Wi-Fi. Whatever it was, it was working regardless.
I have 3 slots open right now. One has HDMI above it and the other 2 both have ss with a diagram above them.

Oh. There's blue lining the two ss/diagram slots.

I did. It hasn't done anything. Like... There's been no noise signifying something new was added. Nothing popped up on screen to tell me something new was added. I'm just assuming it's working.

There we go!
It didn't bing-bong when I plugged it in originally but it did when I pulled it out just now And when I plugged it back in to a different port!
Thank you so much Bruce and Peter!
Hopefully this solves the problem! If it doesn't - I'll be back. lol

Should I go into something like 'Settings' or 'Control Panel' and click on Wi-Fi or does it automatically hook-up itself?

Ummm... Do you have any idea why this dang thing stopped playing DVD's? House is in a hollow so I lose Internet often. (Any time the weatherman even hints at wind. smh) When that happens, I'm lost w/o Hulu (We don't have TV.) so I normally throw a DVD in computer. (I pretty much live in my bedroom.)
About two months ago, computer stopped playing DVD's. I don't have any idea why. It plays videos I've sent it from my phone but it won't play a store-bought one.