Could you confirm there are no stuck keys on the keyboard? Especially the Page down and Down arrow keys. Try connecting an external keyboard and mouse to check if that makes any difference.

If you've Dell support assist software installed, Please run a test on the keyboard to check if there is any other key that has an issue.

Also I suggest you to run a EPSA diagnostics to confirm other parts are fine.

To enter diagnostics, Keep tapping F12 on the startup Dell logo that comes as soon you press the power button.

Select "Diagnostics" from the list, Run it completely and let us know if it passes, Else please reply with the Error message and validation code, we shall take it further.

Hello @AdrianG001,

As per your suggestion, I run the EPSA diagnostics and there was no error report, the test ran successfully. Earlier I tried using external keyboard and mouse yet the same issue, the page was scrolling on its own. However, this time I tried to uninstall keyboard and touchpad driver and use external ones and for now it's not scrolling down. What do you think is the reason? and also it is because of overheating of laptop? because whenever this issue happens the area near the processor fan is unusally heated up.

Everytime I restart the laptop the drivers are already installed so I don't think the solution I mentioned above will work out.

same is happening with me with dell 5558 series. it doesn't matter if i am opening web browser or normal page in my laptop. it is coming back to top every time.  still didn't find any resolution.

Replying to an old thread -- I just had a similar problem on a Precision 3650 tower running Windows 11.  A hard reset of the system fixed the problem. 

1) Unplug the machine and all peripherals

2) hold the power button for at least 10 seconds to drain residual power

3) replug and restart the system

Replying to this old thread!! 
My inspiron 15 3000 series laptop giving me the same headache.
It is scrolling down to the bottom automatically no matter if i'm in the home screen or browsing..
after restarting the device 2/3 times i can able to use it for a while, then it starts again.. I think it is the touchpad problem, not sure though.

Using external mouse to bypass the issue

Same exact issue- SO annoying.  I wonder if this is only Dell PC related or on all PC computers?  I have to restart then I get a couple hours of work done until it starts happening again.  There are no keys 'stuck' either.  I use a bluetooth external keyboard and mouse and it's not stuck either. So frustrating.