log on as administrator. control panel / device manager. Look under mice. If there is a "Dell touchpad" or "synaptics " or whatever touchpad you have you need to disable it, if there is a disable option.
Now for the proper solution. Many trackpads appear as normal mice under Windows. So that when Windows loads it sees a normal mouse connected and installs its standard drivers. In many cases it will say PS/2 mouse.
You need to disable the built-in drivers for this "PS/2 mouse". When Windows loads it will still see the "mouse/trackpad" but will not be able to load he PS/2 mouse drivers. Find "C:\Windows\System32\DriverStore\FileRepository\msmouse.inf_amd64_neutral_7a5f47d3150cc0eb"
and inside this directory find "sermouse.sys" which you must rename to "sermouse.sys.old" (or something). To do that you will need to take ownership of the file : right click, security, advanced, owner, edit, change owner to administrators, all the way back out, then properties (again), security, edit, get the administrators in and give them full control. After that rename the file.
Then you go to "C:\Windows\System32\drivers" and do the same renaming to "sermouse.sys".
Also in "C:\Windows\System32\drivers\en-US" the same to "sermouse.sys.mui"
After all that go to Control panel - devices - mice - right click on the PS/2 mouse and "disable".
Reboot.