going down the lines of being a possible hardware problem, have u tried the card on another network point - or a known working point?

Have you tried the latest drivers for your card? or even the not-latest-but-different drivers that your could find?

only other thing i can think of is duplicate DHCP bindings. that can cause some weird **** when the DHCP database gets a little confuddled and hands out several IPs to one MAC address/name combo. although you receive an IP address and only one, it seems to cause some wierdass problems.

thats it for me