If the pc and laptop both have an ethernet port then just buy cat5 crossover cable, then run windows network setup on both pcs and and select share folders.
Theres some on ebay all differnt size lenghs, remeber you want crossover cable if your only networking 2 pcs.
If both computers do not have a network card (which are cheap anyways) you can also network using a special USB cable, assuming that they both have USB ports.