Getting the circle with line thru it, cannot play some games???

[Eyeball]

On some of my games, I am getting the circle with the line thru it stating that my system has been tampered with.....OH MY GOSH!!! What will I do....Maybe I should call the number? I dont think so...Anyhow, the question I have is, isnt there a code or something I can put in to make it play these games? I read about something like that before but do not remember where. This is on a PS1, with a chip. Thanks