What protocols are you using? if you can browse the network it just means that you are able to receive the master browser list from the PDC or BDC. If you can see individual PC shares then it means your netBIOS is working. if you can ping by name it means your WINS server is running. So the only thing left should be protocols. Make sure that if you are using IPX/SPX that your frame type is set properly (e.g. 802.3). Pas that your best best is to completely remove everything from your network control panel and re-install it before further digging. Go to a machine that is working and make sure EVERY single setting is the same.