no chime, fans go max, black screen, white light stays steady

Hi,

If computer is off, but power is plugged in, number 1 diagnostic LED is on.

If computer is on, no chime, fans go max, black screen, white light stays steady and number 1 and 2 diagnostic LEDs are on.

If LCD unplugged and external monitor plugged in, can't turn off, it turns right back on, once external unplugged, it turns off.

Also tried with detaching everything (add on cards, hard drive, etc.), no results.

Hoping for the power supply...

Any ideas?

Thanks!