You've done the stack repair, and attempted to enable NETBIOS over TCP/IP, right?
If you still have no NETBIOS, let's look at this.
Check your Services are Started on all PCs:
- COM+ Event System (for WZC issues)
- Computer Browser
- DHCP Client
- DNS Client
- Network Connections
- Network Location Awareness
- Remote Procedure Call (RPC)
- Server
- TCP/IP Netbios helper
- Wireless Zero Configuration (XP wireless configurations only)
- WLAN AutoConfig (Vista wireless configurations only)
- Workstation
Note: You can check the services in Control Panel, Administrative Tools, Services. All of these services should be started, and their startup type should be automatic (or perhaps manual).
If a service is not running, open it's properties and check the dependencies. Check each of the dependencies and see which one is preventing the service from running. Checking the event log is also a good idea here, there may be clues to what is failing.