Have you tried a different SATA port? Your port may be malfunctioning, or it may be disabled in the BIOS (in which case you could re enable it).
I tried all the 4 ports of SATA available in my board and it was not working in either of it so i dont think it is a connection problem.
When i checked my BIOS for SATA setting, it was greyed our and 2 ports were disabled.
Please let me know how to enable it and i've windows 7 os with intel motherboard.