I need help my sims 3 will not install.?

Every time i try to install sims 3 i get error messages with a retry button, i click the retry button and it keeps going but the errors keep coming up, i keep clicking the retry button and it keeps installing until it gets near the end. The errors keep coming up but it doesn't go anywhere. I have tried waiting but it goes for like 4 hours. I have looked up solutions online and i either can't do them or they still won't work. I checked the disk for scratches and stuff too.