Changing the order of photoshop layers!?

Help! I need to change the order of the layers of my photoshop pic.

I want to fill a circle completely black, and then adding a different pic / layer on top. How can I do that? Please help. Thanks

PS. I'm using photoshop CS2, if that helps you in helping me in any way.

Changing the order of photoshop layers!?virus

Click and drag the layer you want to move to top over the other layer in the layer pallete. or use ctrl+] and ctrl+[ to move layer up and down

Changing the order of photoshop layers!?anti virus

Just drag the layer you want on top over the other layer in the layer panel?