Does it ever crash w/ an error related to acpi.sys?? Or check in your system log and see if there are errors in there about ACPI. I had this same problem on an abit VP6 and I simply replaced my acpi.sys in Windows\system32\drivers w/ an acpi.sys from win2k. I'm not sure how good of an idea this is but it seems to be working for me. I suggest you rename the acpi.sys file from XP rather than delete it.