Machine can't be seen while BFE is running

I have a strange issue with my Vista Ultimate laptop that stared a
month or so ago.
No other machine can access, or ping the machine.

I've found that by disabling the BFE service however it reappears
again and that the machine can be pinged.

My first thoughts were that the Windows Firewall was the issue since
service relies on BFE, however this is not the case. I can disable
the Windows
Firewall service and the computer remains uncontactable.

Various articles I've seen recommended that disaling BFE was not
a good idea as it compromises security.

Does anyone have an idea what may be causing the issue?