Got New Dell Laptop, W10, 4th computer w/continued problems

Dell Inspiron 15 5000 Series/Intel i5-6200u 2.3ghz/8gb ram/1tb hdd
I'll bet nobody ever had this situation. Past year, 4 different brand computers. W8 and W10. Internet Explorer.

* Often have to click multiple times when I go to click on something.
* Typing, the cursor disappears, or it jumps somewhere else (and touchpad is turned 'off', I am using external mouse). Letters wont appear, keep tapping, or hesitate as I wait, then they might all of a sudden fill in.
* Click to a page, often wait and wait while the page slowly fills in as "circle" goes around.
* When scrolling, I turn the wheel, it hesitates a couple of seconds, then it moves.
* Very often get messages like 'Internet Explorer is not responding' 'the page is not responding, IE is looking for a solution'.
* Often get the cursor flashing, doing the arrow/circle, arrow/hand, hand/circle, wont change to the hand. Happens everywhere, email or 'regular' website pages, etc.
* Yahoo email often seems fouled up. Jumps around by itself. Try to drag an email into a folder, but it wont change to the envelope icon so nothing there to drag.
And more 'weird' things seem to happen.

Had Comcast techs check the cable/internet wiring 3 different times in past, as I felt sure they somehow must have wired something wrong. Nothing. I use their own gateway router/modem, always current.

It wouldn't set up right out of the box, after first couple of steps, screen went black/blank, wouldn't turn back on, called Dell, they did remote-repair. Then earphone jack didn't work, and screen froze 3 times that day. Called, did remote repair again for earphone, said he checked/fix the freezing. I listened to some audio with earphone, was fine. Unplugged it, later go to use it again, does not work again. Sent email, waiting for the next remote-repair. Wondering if I got a "lemon" (again).

This seems incredible to me, four different brand computers, w8 and w10, similar problems making it so frustrating.
Others I've talked to say the same. Am I cursed??

Wow, I'm not a 'techie', a clean install is pretty complicated, isn't it? I wondered when buying a new comp, if a "new" W10 is in it, or if the same working issue of W10 from old comp transfers onto it or something like that? If a new comp comes with W10, isn't that a "clean" issue of W10?? Doesn't seem logical to automatically have to install W10 on a new comp that came with W10.

Anybody have more ideas? Internet Explorer fouled up? Or is that also "new/clean" with a new comp?

It sounds like you have multiple issues. I would return the laptop back to Dell as a new laptop should not be behaving in the ways you described. I am mainly talking about black screen and headphone jack issues.
As far as the internet goes, in my experience Internet Explorer does have some issues resolving a lot of web pages, Yahoo being one of them. Have you installed and tried a different browser such as Firefox or Chrome?
If that makes no difference, if you have a friend with a good working computer come over and see if the internet works any better on their pc. If it doesn't, call Comcast and make them look at your equipment again.

Lots of times, pre-installed systems are junk. I've bought multiple laptops that I needed to do clean installs on due to the Windows that came on it is junk. It sucks, but it's true unfortunately.

Whenever I buy a new laptop, I'll make the recovery media that comes with it, then do a clean install.