Computer motherboards have pci buses, but usually you cannot access this on a laptop.
If it's a card plugged into the side somewhere on a laptop, it's a PCMCIA card. I forget what it stands for
People Can't Remember Computer Industry Acronyms

. Try these commands
icfonfig eth0 up
ifconfig eth0
Please clarify if it's an internal network card, or one which is removable. You might also see it in the output of
lspcmcia
lsusb
lspci
lshal
They may need root permissions, e.g.
sudo lspci
and if you need a paged output, use sudo lspci |less