I've read all your forums on the subject, but none address my particular problem. I'm running WinXP S3 on the same computer that I have been using since 2000. I have done no recent upgrades. Suddenly, one morning (this is key), I start up and get the BSD that my computer is not ACPI Compliant. I shut it down and try again and voila it works. This has been happening for over a week. I need to restart 2-6 times and then it works. I found that when I let the first start up sit for a few minutes without shutting down, it starts up the second time (go figure). I've done a clean install and still have the problem (the clean install is from a disk image that has worked for many months). What's craziest is that during the day, if I shut down and then start up (not a restart) it works perfectly. Any clues?