New Hard Drive is not saving window

hi dear friends, I am using HP 7800 system, I have installed 80gb hard drive previously, now I have installed another 500GB WD sata hard drive, the 500gb hard drive is not saving the windows though it saves for 10 to 30 hours only and sometimes it not only dont show windows but also does not show the harddrive on system, I did new partition and also formatted the new hard drive, can anyone please tell me why this problem is appearing and what is solution of this???