Network your computers.
There is more than one way to do this, but most require you to buy (at least) some sort of cable. Then both computers can be given access to each other's drives by enabling sharing on the appropiate drive(s).
More than you'll ever need to know about networking at:
http://www.windowsnetworking.com/j_helmig/contact.htm
If both computers have ethernet ports, you can network two computers without a hub with a "crossover cable". If you don't have ethernet ports on both machines look for the options for "direct cable connection" for the kind of ports you have. ie. parallel, serial, USB & etc.
BTW: For security reasons, it may be wise to do the sharing while you are offline, and then stop sharing before you go back online.