quite a bump but
for using search
you will need a router as the stb will only allocate 1 ip .You could wire the stb to 1 pc as normal then use a crossover cable to 1st homeplug then crossover cable from 2nd homeplug to pc2 and set up connection sharing not the best option. TBH you would be better off buying a wireless router and a usb adapter for 2nd pc this would be cheaper