To find the quest npcs just follow this easy steps
open quest window by pressing Q
1 press Search Mission
2 type down somewhere the coordinates which r shown
3 press this button.. it will open the coordinate system thing
4 at this field enter the coordinates u just typed down
5 press this button to save the coordinates
6 give it a name
7 ur coords window should look like this now
8 u should have somewhere on ur screen now this blue (can be any other color too) arrow which shows u the way to the coordinates of the npc
9 open map by pressing M.. there is now a blue flag at the coordinates u saved
10 when u click with ur lmb on that area u can zoom in and can see it exactly
i know many know this coords thing but still hope it helps some1