Today I added another 512 MB of RAM to the 512 already in my box and I started getting some odd behavior. When I powered it up after installing the new RAM...it POST'd and showed the correct amount of RAM and then proceeded thru the rest of the boot up process...then..when it got to the Windows XP Login prompt...it just rebooted on its own. It came back up and let me log in but then in a few minutes blue screened and rebooted itself. It seems to have stabilized now and I checked the event logs and saw these entries.... AMLI: ACPI BIOS is attempting to read from an illegal IO port address (0x71), which lies in the 0x70 - 0x71 protected address range. This could lead to system instability. Please contact your system vendor for technical assistance. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. repeated several times....but now they seem to have stopped...is this what was causing the reboots?