The Gtr Kid

i think i must have the worst live setup ever and just cant get it to work (not being very technical doesnt help either) i have a virgin media set top box providing internet via ethernet to my vista computer from there it goes from a usb to ethernet converter to my xbox 360 now i have looked around forums to try and find answers but ive given up and figured id try this both my comp and xbox are showing the link is established and ive changed both the xbox and computer to automatically search for networks but my xbox still fails the ip test i called all the technical support lines and they just told me what id already tried if anyone can help tht would be great.