Select statement against a particular table taking forwever

I have been trying to troubleshoot this problem for a while and at this point, I have no further clues. The problem occurs only in a specific table in an SQL Server database:

Symptoms:

SELECT TOP 1000 * FROM Particular_Table /* works fine */
SELECT TOP 1000000 * FROM Particular_Table /* still works fine */
SELECT * FROM Particular_Table /* statement takes forever to execute */

It's a simple plain SELECT query, no joins, and other tables in the same database do not manifest these symptoms.

My observation is that the query gets close to the end, but never completes. The table is not huge, it has about 800,000 records.

I do not have admin access to the server and I am unable to check error logs, but I can run any query.

Any suggestion on how to locate the root of the problem would be much appreciated.