Cd/dvd rom

Hi guys,
i'm Wilson and i wan you 2 help me resolve that prob that i got with my macbook, my cd/dv don't want to work, every time i insert a cd n it eject it quiklly, so i don't know how to resolve it, please ........

1st... Is it under warranty? Always the 1st choice... Does this happen with all discs or just a couple? Have you tried more than one?

2nd... You may want to get a cleaning disc. If the lens is dirty or dusty and cant read the disc properly, it will spit it back out.

i just bought it from a friend, so i think it ain't got any warranty. it makes it with all discs. Until now i haven't try with other.