Communication Link Failure

Thanks in advance for any help. I really appreciate it.
I am getting a strange error message when connecting to a single Sql Server
all of the sudden.
From enterprise manager the error is:
A connection could not be established to ServerName.
Reason: Communication link failure
Please verify Sql Server is running and check your Sql Server registration
properties (by right-clicking on the ServerName node) and try again.
From Query Analyzer the error is:
Unable to connect to server ServerName
ODBC: Msg 0, Level 16, State 1
[Microsoft][ODBC Sql Server Driver]Communication link failure
I am running Sql 2000 SP 3. Both my pc and the server are running Windows
2000.
If I use a different pc under the same login I am able to connect to the
server so the problem must be on my individual pc. I can also connect to
other Sql servers from the pc that is giving me problems. I have tried
uninstalling and reinstalling Sql and I get the same error message.
Does anyone have any idea as to the cause of this?Update...
I am able to register the server via IP address but not server name. When I
register by IP I get the same message that says:
SQL Server registration failed because of the connection failure displayed
below. Do you wish to Register anyway?
Communication link failure
If I click Yes I can then expand the server and view the databases as
normal. When I register by server name I get the same error message but I
still get the Communication link failure when expanding the server.
Help please!!!