guys just another trouble here

i've a Raptor HDD over it i've installed my OS (Win XP PRO) i've attached this this into the Silicon Sata Port and all runs correctly ... but i'm so curious so i've changed the sata port from the black to a 'normal' blue, and it comes out a strange thing, when the mobo/system starts it doesn't recognize any disk installed into my system ... but obviously i can enter in windows normally ...

why this happens? it's really weird . ..