death of G3?

i have an old beige G3 266, i recently upgraded to 256MBs of ram, and attempted to install OS X. after a failed install, even before starting the installer, the computer fails to boot! nothing on screen, no HD activity, and doesn't boot from CD... all that happens is the monitor activates (green light) for about 4 seconds then switches back to low-power (orange light) with no display. any ideas guys?