When To Enable AHCI mode?

[ishraq]

i have decided to install windows 7
My question is when to enable AHCI mode,,After Installing through the BIOS or before Installion
And Will it delete my DATA on other drives excluding System Dirve?

 

[sincreator]

You have to do it before you install windows. You will not be able to boot into windows if you change it afterwards, unless you set IDE mode in the bios.

I also advise unhooking all other drives while you install windows on your new one. Sometimes windows puts a hidden partition on another drive if multiple drives are connected. Then if that drive fails for some reason, windows may not boot.