My son had some trouble with his P4 2.8Ghz XP computer. It turned out to be software, but has left him with an 'interesting' situation.

When the computer is shut down but not switched off at the wall, a phone call or modem connection, in or out, will boot up his computer.

   This only happens when the unit has NOT been switched off at the socket since shutdown. If it has been, and the power reconnected, it behaves normally and waits until the boot button is pressed.

I wondered if there might be a hackers virus that does this, (suspicious, aren't I,) or it may be that he altered something in the BIOS when he was looking at the original problem,
although he says definitely not.

Ideas gratefully received. He's putting the virus-killer through it at the moment.   Chris.