I have a WDC WD20 EARS-00S8B1 drive that is a few years old. Three motherboards give me smart failure on the drive, but when I run Data Lifeguard Diagnostics it seems as if everything is fine with the drive. My question is which of the smart notifications should I trust? I have been receiving the failure notifications for over a year and a half, and so I backed everything on the drive up, and whiped it clean. Any suggestions?