As @Heliosurge says, it sound like you are installing on a Laptop that has 2 graphics cards. an igpu ( integrated graphics card which is usually low power and not capable of VR) and another more powerful but also power hungry GPU - usually an Nvidia mobile card
the installation should be the same apart from you need to disable the onboard graphics card that cannot do VR. so yes the crappier (probably intel igpu) needs to be disabled in BIOS and in device manager.
this link will tell you how to disable igpu in bios: https://blog.usro.net/how-to-disable-the-onboard-graphics-in-bios/
this is how you disable igpu in device manager:
START > Control Panel > System > Select the "Hardware" tab > Device Manager > Display Adapters. Right click on the listed display (common is the intel integrated graphics accelerator) and select DISABLE. Do not select uninstall as this may cause further problems
then make sure the Pimax is plugged in and the machine has been rebooted so it is using the more powerful graphics chip.. then run the pimax install