Hi there hemanth_pv,
Sorry that you are facing some issues with your WD drive. 🙁
Do you have important data stored on the drive? How is the drive recognized by Disk Management?
Is the drive recognized as having its full capacity under BIOS? In case it is not, then the drive may have some internal fault. In that case, you will need to contact a data recovery company.
I would agree with mbarnes86 and say that it may be a good idea to test the drive with WD's DLG tool. The results should show the overall health status of the drive.
It will not hurt to attach the drive with different SATA and power cables as well.(You can even attach it to a different port)
WD's Data Recovery Partners: http://products.wdc.com/support/kb.ashx?id=oH222l...