I have a Pentium 3 computer with Intel i810 motherboard. It is 866 Mhz, 512Mb SDRAM, 20+160 Gb harddisk which is originally showing 20+137 Gb, 16 Mb inbuilt video memory. I have only three PCI slots and not PCI-express or AGP. I want to install a graphics card to my computer. Please, tell me...