[Lucky]

@Lucky - windows 7 - AVG 2014
and... this operation is impossible couse i need a 'right of administrator' and i dont know the password xDDDDDDDDDDDDDDD

ok , try this : Run Command Prompt, Write a net user , you see a offer User Account , and then type net user /username/ * and Press Enter 2 times and logout
for example net user skrzynek *

PS: Did you try the first method in safe mode ? I forgot to mention you