Disk Authentication Failure Sims3?

I recently bought sims 3 nighlife. So now i installed it, every one of my sims games says Disk Authentication Failure Please Insert Sims3. So i switched all the disks for my add ons and it gives me the same message. I checked online and they said to disable DLA or DAL, i forget, but i checked and i cant find it on my disk drives. Why is it doing this? Is Latenight bugged? Cause my normal sims and sims generations worked perfectly. I just got it today and now icant play at all. My LAST resort is to erase all my data and reload my game. To much time and effort lol. Conclusion: How can i make this stop? Please give me detailed instructions, not a link. I really want help. How much could a 11 year old do to a computer -__- Im lost and confused lol. I just wanna play the stupid game. Desktop Computer Windows 7. Thanks!