You can create a primary key for the table when you create it as follows with a CONSTRAINT clause:
[tt]
CREATE TABLE tblTest (Company Text(3), File Text(4), Name Text(50),
CONSTRAINT [Key] PRIMARY KEY (Company, File))
[/tt]
If you are using a make table query, however, these is no way to define the table in the same query. You could eliminate duplicates by summarizing the table on your primary key. For example:
[tt]
SELECT Company, File, MAX(Name)
INTO tblTest
FROM tblEmployees
GROUP BY Company, File
[/tt]