when I am booting my laptop (Lenovo G550) it gives an error message prior to that.. SMART Failure Predicted on Hard Disk O:Hitachi HTS543225l9A300-(PM) Warning : Immediately back up your data and replace your hard disk drive. Afailure may be imminent. Press F1 to continue.. Once it started, it runs smoothly, I also verified its status by running some internal HDD tests by Hard Disk Senitel software..It shows no bad sector , no virus, no damage , normal temperature ... it suggests every thing is OK except its health... Now my question is that then what is the wrong with it..? It may be wrong with plates (dusty) or the read/write heads...then can I go for repair it or replace it...? My system now reminds me every half an hour to resolve this problem since last 10 days... Help me.