The eraser start drawing in Corel Painter Essential 7

Anyone knew the key of this problem? 
I just draw as usual, press "n" to choose eraser but soft\hard mode just start work like brush. Re - install programm does not get effect. . . 
The only thing what i want is drawing, how fix this or return the program to the creators?
And in general, why sew such a function? Eraser erases, pen\brush draws, why complicate?