Question about PCI slot versions

hey guys, I’m trying to upgrade my computer’s graphics card, it’s not made for gaming really in that it lacks a PCI-E or AGP slot, ive only got regular PCI slots. I found a graphics card (EVGA FX 5500 PCI) that requires PCI 2.1 slots, how do i go about finding out my PCI slot version using Windows XP. any help would be greatly appreciated. thanks