No devices in device manager

Hello,
I have XP sp2. My system went haywire the other day. It came on and the start menu bar is different (From green rounded to square gray), and I have no devices in my device manager. The things I have found is that I have no devices, no audio, and my one care virus scanner isn't allowed to boot. I have my msconfig running normal, and have checked everything I know to check. Please help.
Thanks
Mo