It needs to say what it has, and it only says 2 regular PCI slots free. I don't see AGP or PCI-E x16 anywhere on that website. They might have ripped out the videocard slot, successfully nulling any videocards you might want to add.
Pci is old, old. Thats right it need an agp or much better a PCI-e slot for a video card. Youd be silly to buy any system that doesnt have a pci-e slot, in it, for upgrading.
I think I have figured it out. That has a PCI graphics card, but it has an open PCI-E slot. I'll just tell him to buy another stick of 512 on the ram so it'll have 1 gig.