hdri lighting?

hi,its been awhile since ive used blender so im alot rusty.
i used to be able to use hdr lighting in blender,but now i cant,i get ablack screen,
both in blender and yafray?is it still possible?and where can i find atute for hdr in
blender and yafray?

There is a lot of information in the Yafaray user guide:-