We have a Micron desktop computer running W2K Pro. After booting normally, it went into "Sleep" mode, and we've so far not been able to revive it. The "Sleep" button on the keyboard isn't effective, and there is no reboot/restart button on the case. The On/Off button has no effect. We've unplugged the computer for up to 30 minutes, and it immediately reverts to its "sleep" mode. I need help badly--the computer's owner is getting grouchy!