This is not a serious issue but it is annoying me. Last week my A7N8X motherboard started reported a CMOS checksum error, so I replaced the CR2032 battery. The checksum error is gone, but now whenever I switch the computer on at the mains it boots up automatically, without me pressing the button on the tower. I have checked that none of the 'wake up' settings are enabled. What else could be causing it to boot automatically?