NETBIOS will not Enable on Windows XP

Hi, I am begining to lose the plot, as I have a Windows XP machine that shows Netbios disabled when you do an ipconfig. I have tried:

1. NIC settings all correct – Netbios enabled.
2. Bowser / Server etc etc services all started.
3. No error logs in Device Manager.
4. Reset TCPIP using Netsh
5. Checked Registry for incorrect NETBT settings.
6. Read (almost!) every blog on NETbios.
7. Checked all the usual ssuspect applications.

So, do I FDISK and start again, or can someone shed any light on this issue?

Many Thanks,