If you have AHCI enabled in the bios Windows 7 installs a driver
but you also need the Intel Matrix Storage Manager for correct functionality :
You will find it at the intel site - http://downloadcenter.intel.com/default.aspx
Select chipsets - chipset software - intel(R) matrix storage manager - Select Operating System - select Windows 7 (64bit OR 32 bit) - select drivers
- select intel(R) matrix storage manager 220.127.116.113 - download and install.
(make sure you don't download the floppy configuration utility by mistake) - it will show up if you select utilities.