my computer keeps turning on by itself

I purchased a Dell Dimension 8400 in January, 2005 and it ran great until September, 2005.  It started randomly turning itself off and giving a blinking orange power light.  After replacing several parts, Dell gave up and sent me a refurbished Dell Dimension 8400.  How does this relate to your problem you ask?

The refurbished computer would not turn off.  As soon as I plugged in the power cord the very first time, the system turned itself on.  When I shut down from Windows, it powered off and then turns on again a few seconds later.  Here is what you should check:

1. When the computer is starting up, you can press a function key (try F2) to enter the bios setup.  Under the power management settings you may find a setting that causes the PC to automatically turn itself on when it loses power.  Some systems also have settings in bios to turn on when they receive traffic over the network interface card, so check those settings as well.
2. In the Windows Control Panel, check the Power Management scheme.  Windows has an "always on" scheme.

All of those features were turned off on my machine, but it kept powering on by itself anyway.  Dell sent out a replacement motherboard and that fixed the automatic power up problem.  Unfortunately, I am back to square one again because with the "new" motherboard the computer turns itself off after only a minute or two everytime I turn it on.

I am posting messages on this site and e-mailing tech support from work since my home computer is totally useless right now.

I have to agree with you on that one! But no seriously I have that same problem, but I don't actually tell the computer to shut down I press the power button on my remote, I have Media Center 2005. Anybody have any suggestions?

Mike