It all started after I plugged out my Geforce 420p TI in order to check a S3 PCI vga card in my retro P3 machine.

The CF card which is the hard drive was plugged out when I did the test.

When I insert the AGP G4 4200 again, Windows 98 loader stuck.
I could enter safe mode, removed the Nvidia driver, installed it again, and Windows boot up again.

Then it gives me this error:
emm386 not installed insufficient memory
Press any key to continue.

When booting into windows again, it keeps finding a PCI early non VGA unknown driver.
What did happen and how do I remove it? I didn't install any driver.

All the S3 pci card did was posting into bios.