Delete duplicate rows in table without primary key

I don't think you can't do this in 2000 in one statement unless you have a column in the table that can serve as a candidate key, in which case you wouldn't have duplicate rows :-). You will need to select a distinct set from the existing table to a temp table delete the existing data and reload it from the temp table. You may need to drop constraints from the table before starting, otherwise the delete will fail, and add them back afterwards.

And don't forget to be a be a good DBA and do a backup of the data first.

begin transaction

select distinct * 
into #temp from myTable

delete from myTable

insert into myTable select * from #temp

-- Manually check all is good, if not rollback otherwise commit

You could do it with one delete statement: DELETE FROM tbl1;

but only if you create this trigger first:

CREATE TRIGGER trg1 ON tbl1 FOR DELETE AS
INSERT INTO tbl1 SELECT DISTINCT * FROM deleted;

this does assume that there are no constraints that would be violated by deleting every row.