Tether Laptop to Desktop for Wifi
you don't usually need a crossover cable...if the machines are relatively new, the network cards can auto-configure to the type of cable.
OP, connect a network cable from your laptop to your PC. make sure your PC is set to DHCP.
go to "network connections" on your laptop. make sure only your ethernet and wifi are enable, disable the rest.
right click on your wifi, go to properties, and enable internet connection sharing.
you may need to refresh the IP on your desktop, and then it should work fine.
Intel Core i7 920 || Asus P6T Deluxe V2 || Noctua NH-U12P|| 12GB DDR3-1600
GTX 670 || Intel x-25m 80gb || 1TB Caviar Black || Antec 902 ||Antec 550w