After working fine for months, recently my Lenovo Thinkpad X60 notebook computer, running fully patched Windows XP, is randomly going into Standby Mode a few times a day. I know it is going into Standby Mode, because the Windows screen that says "Preparing for Standby Mode" that you would normally see when you intentionally choose Standby Mode appears. It happens when I am actively working away (e.g. using the mouse while busily working on something) so it isn't a matter of the machine being idle. It always comes right back by pressing the Power button, just as it would normally come back to life if you intentionally chose Standby Mode. I am plugged into the wall and the plugged-in indicator is visible in my system tray, so it is not a matter of it trying to conserve battery power. I have tried a full virus scan with AVG, and things appear to be clean.. same with spyware scan with ZoneAlarm.