if both desktop and laptop have network card,
you can connect them with one cross cable (different from the one you use to connect desktop/laptop to network socket)

then configure the two computer's ip to be in same sub-network, say

192.168.1.100 and
192.168.1.101

then you can do ftp or network sharing within the two.


USB data transfer suite is available in market, around S$50(??)
it connect two pc with USB cable, and need to install software driver.


for serial port cable i never tried, but it should be working in some way.