For the question, you wake up the computer and remind it what to do, the answer is bios.
People are what will wake up a computer and remind it what to do. It cannot read a human's mind.
Sure, I can remind you to wake up when September ends.
The wake button.
Wake up, Neo.
Press the power button on your PC to wake it up
Try pressing the power button again.
Plugging something in (or removing something) is seen as a sufficient action to wake up the computer, since you may be about to do something with it.
You could press the power key on the computer or Click the mouse a few times or Press some buttons on the keyboard. Most graphics tablets won't wake computers. Sometimes moving the mouse will wake the computer.
It's not possible to have Windows XP wake up itself. While it's "sleeping", no applications are running. If you're in a business environment, you can set up another computer to transmit a Wake-onLAN packet to the computer. If your network card supports it (many Intel cards do), you can set it up to wake the computer out of sleep mode. You may also be able to do this with some home routers, such as those that run DD-WRT. A better option may be to set a wake up time in the BIOS (if available) and then shut down the computer completely.
Shake that mouse and wake your computer up.
Sleep puts the machine in a low power state, suspends it (RAM is still on, HDD is off) Wake up literally wakes it back up.
People are what will wake up a computer and remind it what to do. It cannot read a human's mind.