Ok, working on a 2.4 GHz P4 MPC ClientPro. It was having video problems (internal video), and after determining that the CPU and RAM were good, I ordered a new MB. Now I am having the same exact problem....You can power up, shutdown, reboot....no problems. Once it become unplugged and plugged back in (power), you can turn the computer on, but there are no BIOS codes and there is no output. All fans are spinning and power is flowing, but nothing else. You cannot get a proper boot until you reset the BIOS by physically removing the battery. Any ideas on what's causing this??