application properties – attributes

when you rigth click on an application and go to properties and it has the attributes at the bottom for example like read only, archive, hidden, system. on a particular file it has a check by system and the system box is gray out but i can still see the check i need to take that check out. can anyone please tell me how to take it off.
thankyou
if you have an answer please email at victor_m_m@yahoo.com