How do you autowake Windows XP?

Answer 1

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.