SOLVED---I don't know how to delete this post. I am embarrassed. The problem was that monitors were not set to AUTO DETECT (the source) so the display was blank. I assumed the monitor knew what input I was using.The original board was indeed bad so the new board was not a waste. Lesson here is don't assume anything.
-----.It all started when I clicked on a link and suddenly the screen scrolled B&W characters and the hard drives began thrashing. I panicked and pressed the power button. I know, bad move.
Anyway, now when I power up there is no display, no beeps, but the power leds work. Monitors are fine. Hard drive leds flash several seconds. I've tried powering up with F8, F10, win logo ad B key. Keyboard lights and works. Also tried booting from repair disks. DVD Disks show activity, but that's it.
Anybody have ideas how to get the screen to show anything? BTW I replaced the Motherboard. Same problem.