The computer has an Intel 810 chipset with a bios date of 11-99. Intel P3 600E ATX case and power supply. No ISA hardware installed. I did try WinME, Win98 and 98 Second edition. These were able to properly shut off the pc. WindowsXP Pro won't for some reason. Anyways, I have to hold down the power button for several seconds to shut her off. I would like to keep XP Pro if I could. It recognized and set up the rest of the hardware nicely, including the DVD reader/cd rewriter. I'm getting the same problem with a pc I built for my Mother a while back. Ity was fine until my Mom insisted that she wanted MS Powerpoint and the required addition of Windows XP Upgrade. It has; ATX case and power supply. P3 500 slot1 (Katmai) A 1998 DFI motherboard with a newer bios installed 6/2000. It had Win98 SE before the upgrade to XP SP2 over top of it. No ISA devices were ever in the Computer.