My disk drive is recognizin some disks but not others of the same type

I have an Acer laptop with windows vista 2007. I have some computer games installed, namely Sims base game and 2 successfully installed expansion packs. However there are two expansion packs I have bought that the disk drive wont read. It recognized and installed the base game with no trouble and then it wouldnt recognize the next expansion pack I bought. Then I bought a different expansion pack and it installed fine. Then I bought two more at the same time, and it recognized and installed one but not the other. I took the disk to the shop and swapped it for the same game, and it still wont recognize that particular game, but it will the other one. When I put disk in it makes a wirring sound and aftter a while says it is a blank disk and gives me the option of burning content onto it  . Why are some disks of the same type working and others not? Please help