its a poser bug - as you load newer light sets, if the lights have different names, instead of replacing the old lights it will create new lights and turn the old ones off. it also may transfer targetting information from the old set to the new set, thereby messing up your presets. as for some people 'using' so many lights in commercial or freestuff light sets - oftentimes they just do not delete all of these junk lights from the scene. other times, the lights are actually on, just at a very low intensity. for example, in my proluma light set, i have 24+ lights in the global illumination presets, and they all look 'off'. theyre not, though - theyre set at a very low intensity. as for deleting all lights in a scene - there really is no way to do it easily in poser standard. in propack, you can write a quick python script that will delete all the lights in a scene for you, or even change their intensities, orientation, etc. there are some of these in freestuff, i believe - so if you have propack then grab em. if you DONT have propack, get it ;) its really superior - and the renderer is improved as well, which isnt even in its documented features. i can usually spot wether a render is propack or standard - and if you render the same scene in each program, you will see a large difference. also the split viewports, max/lw plugins, little tweaks and python scripting make it well worth it. cheers, -gabriel