What FSB setting are the MOBO jumpers set at, check em against the Duron FSB.
I just did a re build,existing Duron 1300Mhz on to a new K7S8EX,like yours, at first the screen was blank. So I dropped the jumper setting on the MOBO to FSB 200Mhz, and WALLA we had Vision on.
By the way WELCOME to the board monster.