Jump settings on the m/board spring immediately behind but Voodoo cards normally happily settle themselves in - even in the BIOS. But best check the little book that came with it.
Did you follow the manufacturers instructions. Sometimes it is necessary to load the CD first. Have you got DirectX8 'cos that card needs it. 7a will do but 8 is much better.
It might be a good idea to start over too. Works wonders sometimes.
Or you can go Control Panel/Add New Hardware etc.,
It really should be a simple addition! Hope it helps anyway.