motherboard indicator light - won't boot

This morning the desktop won't boot. There's a click, some red leds flash on the memory boards and then everything's dead except for a red led glowing on the moherboard near a reset botton. The reset button makes it go out. Another reset button next to the first causes a yellow led to glow when it's held down. completely reseting the machine has not solved the problem (unplug from power and wait 30 seconds.