I have a pc w/ a motherboard that has pci slots / agp slot..and have pci-express x16 video card..any solutions?

the pci slots on my motherboard are regular old pci slots.

I've seen solutions such as:

- a pci slot to pci-express x1 adapter (but I need x16, i think)

- read about an adapter between agp and pci-express...

I am just not sure what I need.|||an agp video card.|||or a pci-express x16 motherboard!