Enable ahci in windows 7 without re-installing

set bios back to ide,boot into windows then do this,it will re-install the ahci drivers without reformatting/re-installing windows

to enable ahci in windows 7 without re-installing
1.Exit all Windows-based programs.
2.Click Start, type regedit in the Start Search box, and then press ENTER.
3.If you receive the User Account Control dialog box, click Continue.
4.Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesM sahci

5.In the right pane, right-click Start in the Name column, and then click Modify.
6.In the Value data box, type 0, and then click OK.
7.On the File menu, click Exit to close Registry Editor.

restart pc and go in bios,enable ahci and save exit,then when you start windows again it will install the ahci drivers