Hi DjM... sorry not been around to answer... been watching a film on TV

to be honest MsMittens has suggested pretty much all I was going to suggest... but you say the desktop has no valid IP... have you tried pinging the loop back IP?

I admit the cable theory is a weird one... but it is possible that a couple of the wires inside have gone so I'd agree with MsMittens on that.

Only other thing I can think of... is have you tried reseating the NIC on the desktop - maybe one of the contacts has lost it slightly (maybe even worth taking a little surgical alcohol to it to clean up the gold connectors - be careful if you do this won't you!)... long shot I know but could be worth a go.

It is a hub and you bet I'm firewalled.
LOL... glad to hear that

Z