Well, I did some swapping. I somehow ended up with the sticks that shipped and the two mismatched sticks that were in the laptop to begin with. The two sticks I ordered only registered as 3gb, no matter what configuration. I swapped in one of the mismatched sticks with a stick that was clearly labeled as 2gb, and poof - 4gb. So, the upshot is that I ended up with 4gb being recognized, but one of them is clearly either mislabeled or defective. Thanks for the suggestion, as it ended up working out!