PNP keeps changing display adapter

The plug & play on my computer keeps changing the display adapters. I reload
my display adapter, and it will work fine for a couple of days, then it
changes it to the
standard VGA adapter. The monitor is an eMachine 17" eView VESA. I've
turned off the PNP in the control panel. I find my adapter in the selection
list and when I try to download it, it tells me it won't download it. Does my
computer have a mind of its own?...lol I don't know if this is the problem
but I have a OEM computer, it always gets detected as having Windows 98
installed, but in fact it runs WindowsME. The computer is an eMachines with
Intel FW82810 FC-PGA
Celeron CPUs Integrating on-chip Graphics controller and Memory Controller
Hub (a built in graphic card). I hope someone can help. Thanks!!!