[Sgt. Paine]

So im trying to use the burn tool, and i have the exposure on 100%, but nothing happens! the same thing happens with dodge, sponge, sharpen, and blur. everything else works.

[Magnum]

Stupid question: Are you on the right layer? Also, for the burn/dodge, make sure you have the shadow/midtone/highlight setting set so it will do something noticable. Also make sure that the brush you are using has good size and coverage so you can actually tell the difference.

[Apocalypse | NoW]

make sure the layer is raterized (if possible.) Thats usual only needed if you want to burn/dodge a pattern

[[DAS REICH] Blitz]

Its prob the rasterization of the layer as stated previously.