LMAnnounce I presume ?

Hi Techies,
I have a 98 and 2000 network with an NT domain controller.
There is a 2000 machine that periodically can only see SOME of the other machines. All other machines can see and surf to the this machine all the time EXCEPT one 98.
Then with no intervention onmy part the 2000 machine can see and be seen just fine.
My problem is that
1. I’d like some explaination wof why it happens
2. The 98 machine belongs to the boss who needs to use the 2000 machine’s printer to print confidentialdocuments.
Any ideas ?