Are you sure your shutting it down, rather than putting it into stand-by or something similar?
If your turning the computer off into standby mode, any mouse movement or keyboard press will power it back on.
Also you may have a setting enabled like WAKE-ON-LAN or something like that, which powers your computer back up if it detects network activity.
No, i am shutting down. it closes windows, say`s shutting down, turns off,, then restarts..
i had an old msi board that in the bios had a "wake on power mngmt. option " that caused that machine to do the same untill i figured it out and turned off in bios,, i checked last night before i posted,
and turned off WOL. and can`t seem to find any thing else ? also checked advaced settings in software
power on after error is not checked..
1. Check the BIOS for a setting called 'WAKE ON LAN' If set then any network traffic that goes to your PC will start it up --- Opps, see that you know that one. There are some similar timed startup options that will turn the PC on at specific times, guess you checked for them too.
2. The power on/off switch is an intermittent switch. Pull the cable off the power switch (getting rid of an intermittent short in the line). See if the system stops restarting. Can you post how soon after you turn it off that the PC powers on ?
3. Some fails on shutdown will cause a PC to restart. This is a windows option, and might look like the PC powering itself back up. oops, see you have that one too "power on after error is not checked.. " Does the PC completely shutdown, power off? If you pull the wall cord, wait 2 mins then plug in the line cord how soon after that does the PC power up ?
4. Do you often take power hits? another bios setting tells the PC to boot up after loss of power.... A power hit would cause your PC to start up, so would someone toggling a power strips on/off button
5. Any other signs of poltergeist activity ? Ectoplasm ?