What SD says ... something is wrong with the IP setup the pooter is getting from the WiFi.
Are the other machines on the network using the same WiFi connection, or are they hard-wired? [Edit - RTFQ, Keef] Since they are wireless and working right, it points to a problem with the pooter.
Do you have a cable so that you could connect the pooter direct to a port on the router? If that works, some more ipconfig /all with that link working would reveal useful stuff.