As far as I know (95% sure) the GeForce 3 needs a voltage of 3.3. All GF4 cards or higher use 1.5v. All AGP 8x cards use 1.5v but also there are AGP 4x cards that use 1.5v like the older GF4 cards.
Hmmm, makes me remember my first GF3, the first ASUS 8200 card in Holland, I had a sample model of it

(those cards had problems with mouse pointers).
If this is wrong what would the symptoms be? I turned it on several times with no post errors and no video. Could I damadge something?Yes you could damage it, but donīt worry about it, it will take a long time. Just go for a AGP 8x card, just to make sure that you will be safe. I wonder if you can run any 3D appz...