How do I add auto_increment to a column in SQL Server 2008

Question

I am using SQL Server 2008 and a primary key of a database table I am using is not an IDENTITY column (not sure why). I need to change that.

I am in SQ

Answer 1

To illustrate Martin's point:

And PS: - as Mikael Eriksson rightfully mentions (and documents nicely), this Identity Specification remains grayed out as long as that column you're working on has a default constraint.