the pci slots in my dell dimension 4400 are not working the sound and network card are not listed in the device manager. I installed in all 4 slots and tried a good network card and still the same. the rest of the system ok, Is this repairable with drivers from dell ?
The PCI slots might be bad or your chipset drivers may not be installed correctly.
Install the latest chipset drivers for your board. If still nothing, look for a BIOS update that may fix this issue. If still nothing, then I would aim to look for a replacement motherboard, unless you can use what's onboard.