Vista problem

I have an HP Pavlion DV2000 that had a bad hdd (click of death) so I installed a new hdd everything was fine until the other day when i boted it up and it asked for the windows dvd i used the repair option and it worked for a few days then again it asked for the dvd this time the repair option couldnt fix it so i did a fresh install deleting and recreating the partition and formating it that too worked 4 a few days and then again so i went through the sme steps and again got the same result after a few days it asks for the windows dvd. what the hell is going on can anyone tell me please?????