I just bought a new Gigabyte M61PME-S2P and AMD Athlon X2 250. I set everything up with XP Pro on a Viewsonic Graphics Series G810. Everything was fine. I unplugged everything and set the PC up with it's own monitor, a Viewsonic Viewpanel VG150. The computer would not power on at all. through removing each component and retrying the power button I came down to the monitor as the problem. I tried keeping the monitor unplugged, starting the PC and then hooking up the monitor. The mouse and Keyboard would not work. I tried starting it with the G810, and then switching to the VG150, and the mouse and Keyboard would die as soon as the VG150 was plugged in. Any clues?

The monitor worked perfectly yesterday on a different computer. I can try a different cable though;

Tried a brand new cable. Power3ed the system down, plugged in the new cable to both Monitor and PC then tried to power on, and nothing. No power to PC at all. Plugged in a new Acer X203H, and the PC powered up just fine with full keyboard and mouse support.