Question : Problem: Will  PCI express slot accept a standard PCI graphics card?

Currently using the motherboard's graphics.
This model of Presario has amethystM-GL6E motherboard which has one PCI express 16X slot.

 I'm looking at a low-priced card that should improve performance with Blender and Second Live (I'm not a serious gamer- I'm a retiree that "piddles with 3D stuff, etc)
This is a very low-priced card, but may be better than what I have. (If it fits that PCI express slot)
GEFORCE2 MX400/TV-OUT/PCI/64MB DDR - VIDEO-118PCI-64DDRTV

Thanks all

Answer : Problem: Will  PCI express slot accept a standard PCI graphics card?

No, a PCI card will nor work in a PCI-e slot. The Presario SR1610NX has 1-16x PCI-e slot and 3 standard PCI slots, the PCI video card will work in any one of those 3 slots.