The answer to go into the bios on the 531 and change the Sata ports to 1 and 2 was exactly the right answer. Worked like a charm. This is something I never would have found anywhere else and didn't seem to be in the owners manual. I am currently involved in a "project" to upgrade a 531 as much as possible with a new larger HDD and DVD writer and installing the max memory to 4gb along with a upgraded Athlon 64 x2 5600 at 65w. Hopefully this won't mean I need a bigger power supply too. If I have a problem, I will look to this community for solutions.