:p I've dyed my hair dark brown. If i get a hair lightening product and it turns ginger. When i put the desired colour on will it be okay?
(I put a lightening product on before when it was dark blonde and it turned out blonde roots, orange hair.)

The reason you had blonde roots and orange hair because you must have applied the hair lightener on the roots first which is a NO NO. Heat from the scalp speeds up the processing. So therefore you ended up with blonde roots. So when you do apply a lightener, always make sure you apply first to midlengths, then ends, then the roots.

Also, when bleaching hair, the bleach is stripping out colour one by one starting from the darkest. First takes out the black, then brown, then it goes to red-orange- then light red orange, then blonde to light blonde and so on. When bleaching always keep a wet cotton wool handy so you can take off a bit bleach and see if it has reached the desire colour. :)