It is possible you have the same problem than me with a brand new WD scorpio blue 1000G disk.
WD never told me that this disk has native 4k sectors, and thus IS NOT SUPPORTED by windows 7, as you can check there :
http://support.microsoft.com/kb/2510009
http://support.microsoft.com/kb/982018
http://msdn.microsoft.com/en-us/library/windows/desktop/hh848035%28v=vs.85%29.aspx
I don’t know how you can check that, you should ask WD 
