have 2 pci slots have tried shifting cards to both slots a total of 5 modems all pnp but xp pro will not pick them up tried video card and no luck either just black screen any ideas how I can confirm if pci slots are duff??
Most important (you may already know, but just in case) - you must unplug the mains, or switch off at the mains or on the back of the PSU, before changing internal devices in the computer. Just powering down from the front panel, or the software switch off routine is not enough - power is still left on the motherboard and can blow cards, RAM, etc.
When you change/add a PCI card, on the first bootup always go into the BIOS and Enable the PCI configuration reset. This allows all the PCI cards to be re-detected and their IRQs to be sorted out again. It will automatically reset itself to Disabled after the next re-boot.