seagate hard disk — After replacement every time i got faulty hard disk

Hi,
I am using Seagate 80GB Hard disk and have 5 years warranty also, but i faced problem with this hard disk. so i replaced it but after replacement i got faulty hard disk and this process repeated 3 or 4 times. now 5 to 6 months has been past. what the hell is going on when i will get the correct hard disk. do you think this is a joke.